I believe the answer would be C, however I read it last year and my memory sucks<span />
Answer: According to Benvolio, the fight was caused by the servants, whom he found already fighting when he got there.
Explanation: In this scene from Act 1, Montague, Benvolio's uncle, asks him who started the "ancient quarrel," and Benvolio replies by saying that Montague's servants were already fighting his enemy's servants when he arrived. He drew his sword in order to persuade them to stop the fight, but Tybalt arrived and he challenged him. They started fighting too, and soon other citizens joined them.
