选择合适的选项补全对话。A：Hello，John!
B：
A：
B：It's 10：30.
A：Let's go to the music room.
B：OK！
A：I'm ready.Let's go.    
A．Are you ready?
B．Come on.
C．Hi，Mike.
D．What time is it?
E．It's time for music class.