Alice didn't know _____ made her lose her patience and shout at her brother at that time. [ ]

A. what was it that

B. why was it that

C. what it was that

D. why it was that

含硫的化合物香气阈值极低，它们的气味非常典型，一般表现为恶臭和令人不愉快的气味，气味持久难消。