THEY ARE UNIVERSITY PROFESSORS WHO SPECIALIZE ________ THE HISTORY...

13. - 25 DE THI HOC KI 1 MON TIENG ANH LOP 12 CO DAP AN
25 DE THI HOC KI 1 MON TIENG ANH LOP 12 CO DAP AN

13. They are university professors who specialize ________ the history of the Russian empire.

A. on

B. to

C. in

D. about