GMAT的一道语法题

GMAT考试第一道语法题是这样的

xxx spends equal to 150 days ...

A. equal to
B. an amount equal to
C. equivalent to
D. an equivalent amount to
E. 忘了

这题应该选什么了？我选了B, 不知道错还是对。希望大家能帮帮忙解答一下

I agree with you if there is no E. but who knows, maybe E is better than B.

语法题目请在GMAT语法区讨论啊

pumpkin说的对，不好意思阿。我是新手，请见谅！