Sentence Correction

Hi all,

This is the question from official guide of GMAT 12th edition. Can anyone help me understand, why "as well as gesturing" in option C make the choice wrong?

Q.

Researchers have found that individuals who have
been blind from birth, and who thus have never seen
anyone gesture, nevertheless make hand motions
when speaking just as frequently and in virtually the
same way as sighted people do, and that they will
gesture even when conversing with another blind
person.
(A) who thus have never seen anyone gesture,
nevertheless make hand motions when speaking
just as frequently and in virtually the same way
as sighted people do, and that they will gesture
(B) who thus never saw anyone gesturing,
nevertheless make hand motions when speaking
just as frequent and in virtually the same way as
sighted people did, and that they will gesture
(C) who thus have never seen anyone gesture,
nevertheless made hand motions when speaking
just as frequently and in virtually the same way
as sighted people do, as well as gesturing
(D) thus never having seen anyone gesture,
nevertheless made hand motions when speaking
just as frequent and in virtually the same way as
sighted people did, as well as gesturing
(E) thus never having seen anyone gesture,
nevertheless to make hand motions when
speaking just as frequently and in virtually the
same way as sighted people do, and to gesture
[spoiler]
OA - A[/spoiler][spoiler][/spoiler]