请教：, but 后应该加句子的，这题居然没加！

A middleweight black hole weighs in at roughly 500 solar masses, hundreds of times more massive than the lightweight black holes produced by the collapse of individual stars, but
            thousands or even millions of times less in its mass as the heavyweight giants that lurk in the centers of galaxies.

(A) thousands or even millions of times less in its mass as

(B) it is thousands or even millions of times less massive as

(C) thousands or even millions of times less massive than

(D) yet it is thousands or even millions times less massive than  (C)

(E) yet it is thousands or even millions of times less in its mass than

这题从语法点和平行方面选C确实是最佳，可为什么, but 后面没有加句子呢？请教！

这题从语法点和平行方面选C确实是最佳，可为什么, but 后面没有加句子呢？请教！