people didn't know __during the night

问题描述:

people didn't know __during the night
people didn't know __during the night.
A:what was happened B:what the murder happened
C:what happened D:how the murder has happened
怎么选
要有理由哦

d排除时态不对
happen没有被动a排除
选C
B中有事件murder不能加what排除