The environmental community across the globe is currently in the middle of a huge debate

whose aim is not only finding out the feasibility of banning Chlorofluorocarbons altogether but also to determine whether such a move is warranted by the current situation.

(A) whose aim is not only

finding out the feasibility of banning Chlorofluorocarbons altogether but also

to determine (B) which is aimed at finding out not only

the feasibility of banning Chlorofluorocarbons altogether but also

determining (C) that is aimed at finding out not only

the feasibility of banning Chlorofluorocarbons altogether but also

to determine (D) the aim of which is to not only

find out the feasibility of banning Chlorofluorocarbons altogether but also

to determine (E) whose aim is not only

to find out the feasibility of banning Chlorofluorocarbons altogether but also

to determineIt should be E. "not only X but also Y", X and Y must be parallel