Galileo was convinced that natural phenomena, as manifestations of the laws of physics, would appear the same to someone on the deck of a ship moving smoothly and uniformly through the water as a person standing on land.

(A) water as a
(B) water as to a
(C) water; just as it would to a
(D) water, as it would to the
(E) water; just as to the

Can someone explain why choice C creates a Fragment, can't we use would as the main verb here?