Answer:
A) Chris and Molly were delighted to see the whole family gathered in the living room; the group was waiting to congratulate the couple.
Explanation:
When a sentence consists of two or more independent clauses, they need to be properly connected. One of the ways to connect two independent clauses is to use the semicolon. The semicolon is used when the clauses are closely related to each other, usually with one of them explaining the other. This is the case in sentence A.
Sentence B is a complex sentence. It consists of one independent and one subordinate clause connected by a comma. There is no semicolon in this sentence.
Sentence C is the second closest to being correct. What's wrong, though, is that these two clauses aren't closely related to each other.
Sentence D also a complex sentence, and the use of the semicolon here is incorrect, because an independent and subordinate clause can't be connected to each other by a semicolon.
