请教一个关于介宾结构平行的问题

spoooon

请问如果两个介宾结构做平行成分且介词一样的话，介词是否必须补出呢？

比如这道题：

Recent findings lend strong support to the theory that a black hole lies at the center of the Milky Way and of many of the 100 billion other galaxies estimated to exist in the universe.

A.    that a black hole lies at the center of the Milky Way and of

B.    that a black hole lies at the Milky Way’s center and

C.    that there is a black hole lying at the milky Way’s center and

D.    of a black hole lying at the Milky Way’s center and

E.    of a black hole that lies at the center of the Milky Way and of

OA:A

其中A补出of的原因是消除歧义，但是如果没有歧义的情况下还需要补出吗？