This is a GMAT sentence correction problem.

Unlike the original National Museum of Science and Technology in Italy, where the models are encased in glass or operated only by staff members, the Virtual Leonardo Project, an online version of the museum, encourages visitors to “touch” each exhibit, which thereby activates the animated functions of the piece.

A.    exhibit, which thereby activates
B.    exhibit, in turn an activation of
C.    exhibit, and it will activate
D.    exhibit and thereby activate
E.    exhibit which, as a result, activates

The official answer is D.

Both A and C sound awkward. However I am not able to find why they're wrong grammatically. In choice A, I am not sure about if the attributive clause can modify the whole sentence before or it can just modify the word 'exhibit'. In choice C, I am not sure about if the pronoun 'it' can just substitute 'exhibit' or it can refer the whole sentence. Could anybody explain it to me?

Thank you in advance.