下列运算正确的是（　　）

A．a³•a⁴=a¹²

B．a⁵-a³=a²

C．（a²）^m=a^2m

D．（a+1）⁰=1

—Peter, what’s your mother doing now?

—She____________in the kitchen.

A．cooks

B．is cooking

C．will cook

D．cooked