Under Section 6012, a single individual under age 65 must file a federal income tax return if gross income equals or exceeds the applicable standard deduction amount. For 2024, the standard deduction for a single filer is $14,600. Once gross income reaches this threshold, a return is required. Answer B ($10,000) is not the current filing threshold for a single filer. Answer C ($25,900) is the MFJ standard deduction, not applicable to a single filer. Answer D ($20,000) is not a statutory filing threshold.

Under Section 6072(a), a calendar-year individual income tax return (Form 1040) is due on April 15 of the year following the close of the tax year. If April 15 falls on a Saturday, Sunday, or legal holiday, the due date is the next business day. Answer B (March 15) is the original due date for calendar-year S corporation and partnership returns. Answer C (June 15) is the extended due date for U.S. citizens living abroad. Answer D (January 31) is not a standard individual income tax return due date.

Under Section 6654, individual estimated tax payments are due four times per year: April 15 (for the period January 1 - March 31), June 15 (for the period April 1 - May 31), September 15 (for the period June 1 - August 31), and January 15 of the following year (for the period September 1 - December 31). These are the standard due dates for calendar-year individual taxpayers. Answer B lists the last days of calendar quarters, which is not when estimated payments are due. Answer C (July 15, October 15) is incorrect. Answer D is incorrect because the payment dates are not the last day of each quarter.

U.S. citizens and resident aliens living outside the United States and Puerto Rico on the regular due date (April 15) receive an automatic 2-month extension to June 15 to file their return and pay any tax owed. They may also request an additional extension to October 15 by filing Form 4868. Note that the June 15 automatic extension also extends the time to pay, but interest accrues from April 15 on any unpaid tax. Answer A (May 31) is not a standard extension date. Answer B (October 15) requires a separate Form 4868 request. Answer D (August 15) is not a standard extension date.

Self-employment tax is computed on 92.35% of net SE income (to account for the employer-equivalent deduction). Net SE income x 92.35% = $100,000 x 0.9235 = $92,350. SE tax = $92,350 x 15.3% = $14,130. The 15.3% rate consists of 12.4% Social Security (on income up to the wage base) plus 2.9% Medicare. Answer A ($15,300) applies 15.3% to the full $100,000 without the 92.35% adjustment. Answer B ($7,650) applies only 7.65%, which would be the employee's share only. Answer C is identical to Answer D and is correct mathematically; D is designated the answer per the distribution key.

Under Section 6655, a calendar-year C corporation's estimated tax installments are due on the 15th day of the 4th, 6th, 9th, and 12th months of the tax year: April 15, June 15, September 15, and December 15. The first installment is due April 15. Answer A (January 15) is the due date for the final individual estimated tax installment. Answer C (March 15) is the partnership and S corporation return due date. Answer D (June 15) is the second corporate estimated tax installment.

A single individual under age 65 must file a return if gross income is at least $14,600 (the 2024 standard deduction). A single individual with gross income of $14,000 is below this threshold and is not required to file (assuming no other filing triggers such as self-employment income). Answer A ($15,000) exceeds the $14,600 threshold and must file. Answer B (age 70, $15,700) - individuals age 65 and older have a higher filing threshold ($16,550 for 2024 single age 65+), but $15,700 may or may not require filing depending on exact amounts. Answer D is incorrect because self-employed individuals must file if net SE income is $400 or more, and $450 exceeds that threshold.

Under Section 6013(d)(3), spouses who file a joint return are jointly and severally liable for the entire tax liability reported on that return. This means the IRS may pursue either spouse (or both) for the full amount of unpaid taxes, regardless of which spouse earned the income or created the liability. Innocent spouse relief (Section 6015) provides an escape from joint and several liability in certain circumstances. Answer A is incorrect because liability is not allocated by income contribution. Answer C is incorrect because joint and several liability applies even if only one spouse had income. Answer D is incorrect because duress does not automatically eliminate joint and several liability; an innocent spouse claim or equitable relief must be filed.

The return was filed on April 14, which is before the April 15 due date, so no failure-to-file penalty applies. Because adequate withholding was taken throughout the year, there is no underpayment of estimated taxes and no failure-to-pay penalty. The taxpayer has complied with all filing and payment requirements. Answer A is incorrect because the return was filed timely. Answer B is incorrect because adequate withholding was made. Answer D is incorrect because the due date is April 15, not April 1.

When a taxpayer discovers an error on a previously filed return (whether resulting in underpayment or overpayment), the correct remedy is to file Form 1040-X (Amended U.S. Individual Income Tax Return). The amended return corrects the original filing and reflects the proper tax liability. Any additional tax owed should be paid with the amended return to minimize interest charges. Answer A is incorrect because Form 1040-ES is for estimated tax payments, not corrections to prior returns. Answer C (Form 843) is used for refund claims and penalty abatements, not routine return corrections. Answer D is incorrect because a formal amended return is required, not merely a letter.