请选择ABCD6I3P+^2^0G/l9M(B:]'qWe will never forget what happened ___________ the afternoon of May 12, 2008.-o-[*~4A
A. in-o-[*~4A
B. by-o-[*~4A
C. at-o-[*~4A
D. on-o-[*~4A