下列计算正确的是（ ）

A．a²+a³=a⁵

B．a·a²=a²

C．(ab)³=ab³

D．(a²)²=a⁴

— Where is my notebook?

— I don't know. It isn't here. Maybe             took it away by mistake. [ ]

A. everybody

B. nobody

C. anybody

D. somebody