The second world war broke out in __the second world war broke out in __A 1930‘s B the 1930s C the 1930’s D 1930s答案选c,可是我认为bc都是对的,怎么解释

问题描述:

The second world war broke out in __
the second world war broke out in __
A 1930‘s B the 1930s C the 1930’s D 1930s
答案选c,可是我认为bc都是对的,怎么解释