When used in the plural, the "heavens" are merely the sky—as in the whole contents of space. Because of the Judeo-Christian usage "heaven and hell," you are likely tempted to pick "inferno" or even "condemnation." However, the best antonym for the simple word "heavens" is the equally simple "ground." The contrast here is "heaven and earth."

A direct contrast to "sunset" would be "sunrise." A number of these options are good words for saying "not-sunset"—such as "midday" and "noonday"; however, none of these are direct antonyms. The most direct contrast is found in the word "daybreak."

A "deluge" is a flood. It is very hard to find a tangible opposite to a flood, but we can consider the situation in which there is a lack of water. This would provide a decent antonym for us—enough to answer this question at least. Precipitation is something potentially wet (if it refers to rain or snow), and a draft does not directly signify being dry. The other two options are abstract states that do not apply to this question at all. Therefore, the best answer is "drought," describing a period of dry weather without any rain—quite the opposite of a deluge.