1. Many investors base their choice between bonds and stocks on comparing bond yields to the dividends available on common stocks.
(A) between bonds and stocks on comparing bond yields to
(B) among bonds and stocks on comparisons of bond yields to
(C) between bonds and stocks on comparisons of bond yields with
(D) among bonds and stocks on comparing bond yields and
(E) between bonds and stocks on comparing bond yields with

OA is C. But in choice A, what part of speech is the word comparing performing.
I read in a post that 'comparing' is a gerund? Can someone please explain how it performs the role of noun here.

Thanks