请教prep上的一题！

30. The Sports Medicine Programs of the Olympic Training Center, a complex where final try outs are held for athletes representing the US 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  
        

这题答案选E, 我选的是C. C何E就不同在their preparation 和 preparing them 那里。 想请问NN们， 这两个词组有什么不同啊？多多谢了！！

C选项的enhance后面接复合宾语performance和preparation, 而enhance preparation不是一个习惯说法,提高准备说不通,对吧

而E就对了,不会产生这个歧异

choice D violate the parllelism, followed the first "toward" is a noun, while followed the second is a gerund.