[求助]GWD-4-17 答案怎么怪怪的？

Q17:

Last year the price per share of Stock X increased by
k percent and the earnings per share of Stock X increased by m
percent, where k is greater than m.  By what percent did the ratio of price per
share to earnings per share increase, in terms of k and m?

A.   k/m %

B.    
(k – m) %

C.    
[100(k – m)] / (100 + k) %

D.    
[100(k – m)] / (100 + m) % 

E.     
[100(k – m)] / (100 + k + m)
%

答案是D，可我算出的结果是(k%-m%)/(1+m%)。如果考试中我会选D,毕竟D最像，可我不明白结果为什么不一样？如果是我理解题目不正确，那PERCENTAGE也应该是(k-m)/(1+m%)。百思不解为什么D的分子要乘100？哪位牛牛帮帮忙解释一下？