Using Formal and Informal English Appropriately Practice Test

Read about the different situations: Carlos writes a classroom job application, "I am responsible and I will arrive on time." Later he texts Keisha, "I’m gonna be late lol." Which shows Carlos is using informal English?

In these situations, Chen speaks to different audiences: During recess he tells Amir, "Let’s just chill and trade cards." When introducing a guest speaker at assembly, he says, "Good morning. Thank you for visiting our school." Which situation requires formal English?