Im sorry to ask but is this a book?
the answers are the first and last option :)
It seems to be C, but there is not much context providing me to explain myself.
Answer:
After "late".
Unless the caterer is late, this banquet should go off without a hitch.
Explanation:
If you read this sentence out loud, you would give a slight pause after "late", indicating a comma.
Hope this helps!