Answer:
B. Anna said we couldn't leave until the fourth quarter ended
Explanation:
This sentence has an adverbial clause - see underlined pattern-. The adverbial clause is introduced by a subordinating comjuction: until. Then, a clause runs: the fourth quarter ended. There is a subject : the fourth quarter and a predicate: ended. This clause is a subordinate clause because it depends on the main clause: Anna said we couldn't leave ; and it adds information to this main idea. The subordinate clause gives information about time. It is the answer to : When could we leave according to Anna?