A:Should
B:Might
C:Must
D:Could
The computer, help we human beings have stepped into the information age, should be regarded as one of the most important inventions in the 20th century.
15×15=225
34×36=1224
25×25=625
33×37=1221
35×35=1225
32×38=1216
45×45=2025
31×39=1209
28×22=____