求助一道题

The Sports Medicine Programs of the Olympic Training Center, a complex where final tryouts are

held for athletes representing the United States in the Olympics, is geared toward enhancing

athletes' performance and toward their preparation for international competition.

(A) is geared toward enhancing athletes' performance and toward their preparation

(B) is geared to enhance the performance of athletes and to prepare them

(C) are geared to enhance athletes' performance and their preparation

(D) are geared toward the enhancement of athletes' performance and toward preparing them

(E) are geared toward enhancing the performance of athletes and preparing them 

想问下c为什么不行啊？把and理解为和performance并列不行吗？可以是两个名词并列啊，为什么一定要e是两个动词并列才对啊？

那个主语?