I shall never forget those days --- I lived in the army with

I shall never forget those days ___ I lived in the army with the soldiers ,.I shall never forget those days ___ I lived in the army with the soldiers ,______ has a great effect on my life.A:that ; which B:when ; which C:when ; that D：which ; that为什么?B 是怎么错的?错了 我是想问A 是怎么错的？