Of the people who bought about the reformation, the religious revolution that grew out of objections to the doctrines of the medieval church, Martin Luther is the best known of them.

(A) Martin Luther is the best known of them.
(B) the best known is Martin Luther
(C) the better known of them was Martin Luther
(D) Martin Luther is better known
(E) the best known one was Martin Luther

The given ans is (B)

Is the first sentence an independent clause modifying something in this sentence?