请选择DCBA4M9N+t*mDavid goes to school ______ every day.9p:u+k4{9H
A．by a bike9p:u+k4{9H
B．by his bike9p:u+k4{9H
C．on his bike9p:u+k4{9H
D．on bike9p:u+k4{9H