A train travelling at a speed of 75 m.p.h. enters a tunnel 2(1 2)miles long. The length of the train is 1 4mile. How long does it take for all of the train to pass through the tunnel, from the moment the front enters to the moment the rear emerges
A．2'12''
B．3'15''
C．2'20''
D． 3'30''