31. If firm A and B enter a swap contract and let A borrow at fixed rate and B borrow at floating rate, then let firm A pay firm B floating rate LIBOR, and firm B pay firm A fixed rate 8%, then the net cost for firm A each year is , and the net eost for firm B each year is A. (LIBOR- 0.50%)100 million, 8.50%100 million B. 9.50%100 million, (LIBOR-0.50\%) 5100 million C. (LIBOR-1\%) 1%100 million, 9%100 million D. LIBOR 100 miltion, 8.50%100 million