The factory produces half a million pairs of shoes every year, 80% _______ are sold abroad.

A. of which ?

B. which of ?

C. of them ?

D. of that?

 The factory produces half a million pairs of shoes every year,80%________ are sold abroad.     

A.  of them                B. which of                        C. of which                          D. of that

The factory produces half a million pairs of shoes every year, 80% ____ are sold abroad.

A. of which      B. which of       C. of them       D. of that

The factory produces half a million pairs of shoes every year, 80%        are sold abroad.

A. of which         B. which of         C. of them     D. of that

The factory produces half a million pairs of shoes every year, 80% ____ are sold abroad.

　 A. of which　　　 B. which of　　　　 C. of them　　　 D. of that

The factory produces half a million pairs of shoes every year, 80% _____ are sold abroad.

A. of which

B. which of

C. of them

D. of that