1949 was a year __the Chinese People's * was founded.为什么不选D呀?

问题描述:

1949 was a year __the Chinese People's * was founded.为什么不选D呀?
A that B which C when D on which
为什么不选D呀.麻烦给出详解,

选C
因为年的前面只能是 in,on放在具体日期前面
D改为in which就可以了