A pulse is applied to each input of an exclusive-OR gate. One pulse goes HIGH at t = 0 andgoes back LOW at t = 1 ms. The other pulse goes HIGH at t = 0.8 ms and goes back LOW att = 3 ms. The output pulse can be described as follows:
选项：

A:It goes HIGH at t = 0 and back LOW at t = 3 ms.;
B:It goes HIGH at t = 0 and back LOW at t = 0.8 ms.;
C:It goes HIGH at t = 1 ms and back LOW at t = 3 ms.;
D:both answers (b) and (c)