This question is incomplete. Here's the complete question.
The crowd cheered when Ben intercepted the quarterback’s badly aimed pass, then the fans threw half-eaten hot dogs and popcorn boxes as Ben rushed into the wrong end zone, scoring a touchdown for the Boone High Braves, the opposing team.
A. ... pass, but then ...
B. ... pass; but, then ...
C. ... pass, however, then ...
D. No change is necessary.
Answer: B. ... pass; but, then ...
Step-by-step explanation:
In this example, we have two independent clauses (simple sentences) put together into a compound sentence; however, since the second one is in contrast with the first one (although Ben was cheered at first, he gets stuff thrown at him later) the appropriate coordinating conjunctions should be a semicolon followed by "but, then".
The correct sentence would be:
The crowd cheered when Ben intercepted the quarterback’s badly aimed pass; but, then the fans threw half-eaten hot dogs and popcorn boxes as Ben rushed into the wrong end zone, scoring a touchdown for the Boone High Braves, the opposing team.