A,绝对是A!
这里sufferings后面的定语从句实际上把连接词省略了,如果只填连接词,如楼上所说,则定于从句内部就没有了主语,这个句子实际缺的是定语从句的“主语”
不信你看：
Never ever should we forget about the war in Iraq and the sufferings it caused to the people there.
Never ever should we forget about the war in Iraq and
the sufferings WHICH it caused to the people there.
Never ever should we forget about the war in Iraq and the sufferings THAT it caused to the people there.
顺便再说下,当定语从句修饰的对象在定语从句内部作宾语时,连接词可以省略.