What would indicate that a sentence is complete?

A complete sentence must contain at least a subject and a verb. The subject indicates who or what the sentence is about, while the verb expresses the action or state of being. This structure allows the sentence to convey a complete thought, making it understandable on its own.

In contrast, merely having two subjects (as in the first choice) does not guarantee completeness, because there may still be a lack of a verb, leaving the thought unfinished. The use of complex vocabulary (the third option) or metaphors (the fourth option) does not affect the grammatical completeness of a sentence; they are stylistic elements that can enhance writing but do not determine whether a sentence conveys a full idea. Thus, the presence of a subject and a verb is the primary requirement for sentence completeness.