prep2 88

88. Because Miranda, the smallest moon of Uranus, has a large number of different surface features,
            including craters, mountains, valleys, and fractures, some astronomers suggest that at one time
            repeated impacts broke the surface apart, and after which the fragments were subsequently
                rejoined because of mutual gravitational attraction.

(A) repeated impacts broke the surface apart, and after which the fragments were subsequently
            rejoined because of

(B) repeated impacts on the surface broke it apart, after which the fragments having rejoined with

(C) through repeated impacts that the surface broke apart, after which the fragments subsequently
            rejoined by

(D) the surface broke apart with repeated impacts, after which the fragments having rejoined
            through

(E) the surface broke apart as a result of repeated impacts, after which the fragments rejoined
            through

Answer: E

这里的which指什么呢？不是指前面的一整个句子吗？？