It is the hole in the ship,rather tha the floating iceberg,___ is to blame for

It is the hole in the ship,rather than the floating iceberg,___ is to blame for the sunken ship in Antarctic.A.which B.this C.that D.whom答案C,请问为什么选C不选A谢谢因为It is ...that...是个强调句型.句...不能是定语从句吗定语从句的that和which是关系代词，关系代词在定语从句中【要做句子成分】，而强调句型的that(没有which)在强调句型中只是一个【连词】，连词that在强调句型中不做任何成分，把强调结构It is ... that... 去掉，句子依然正确，The hole in the ship,rather thanthe floating iceberg, is to blame for the sunken ship in Antarctic.