请教大全720题

1.        The data collected by weather airplanes that fly into the heart of a hurricane are useful mainly for gauging the storm’s structure and strength, not for the speed and the path of their movement.

(A) not for the speed and the path of their movement

(B) not for the speed and path of its movement

(C) not the speed and path of its movement

(D) and not the speed and path of their movements（C）

(E) and not for the speed and the path of its movements

请教这道题的解答，不明白为什么选c。3Q!

the storm 用单数 its

for gauging .... for doing