求解一道数学题

evey

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,跪求讲解，最好能讲一下题目问什么呢