Thanks,but you needn ' t have ------.I bought a new one this

Thanks,but you needn ' t have ______.I bought a new one this morning.A.
1.Thanks,but you needn
t have ______.I bought a new one this morning.
A.stood B.worked C.bothered D.operated
选C 我想知道每个选项的意思和句子翻译及选择的原因.
有3题我不懂的想问一下
2.One of the men held the view ____ the book said was right.
A.what that B what C.that D that what
3.____ fashion differs from country to country may reflect a cultural difference from one aspect.
A.What B.That C.This D.which
4.The professor spoke very clearly to make his speech easy.
A.to understand B.understand C.understanding D.understood
The professor spoke very clearly to make his speech easy ______
A.to understand B.understand C.understanding D.understood