With diamonds, as with all gems, one should ask for a written description of one’s purchase; the description may prove useful later if you have reason to believe the jeweler misled you.

(A) one should ask for a written description of one’s purchase

(B) you should ask for a written description of your purchase

(C) a written discretion of your purchase is what one should ask for

(D) a written description of one’s purchase is what should be asked for（B）

(E) a written description of your purchase is what should be asked for

同学们，在石林的语法讲课中，是说过绝对不会选含有you 的选项的，因为它造成模糊不清．这题的Ｅ为什么不对呢？