Which choice correctly completes the sentence: "_____ always complaining about the time of _____ curfew."?

The correct answer is found by focusing on the meanings of the words involved and how they fit into the context of the sentence.

In the phrase “_____ always complaining about the time of _____ curfew,” the first blank requires a word that suggests the subject of the sentence, which is a group of people. The word "they're," which is a contraction for "they are," is appropriate because it indicates the action of those people—complaining.

The second blank refers to possession, indicating that the curfew belongs to them. The word "their" is the correct choice here as it shows ownership. Thus, the complete sentence would read: "They're always complaining about the time of their curfew."

This combination makes logical sense within the context, as it conveys that a group of people are expressing dissatisfaction regarding a curfew that belongs to them.