Q18: 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) %

我读不懂题：（，答案是D。请NN指教