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.
Step-by-step explanation:
A semicolon is actually used to link/connect two independent clauses that are closely related in thought. The semicolon is used to connect two or more ideas or clauses which are equal in rank or position.
In the above sentence, the use of semicolon is correct because it joins two independent clauses together. These clauses share a close, logical connection.