A box when dropped from a certain height reaches the ground with a speed v. when it slides from rest from the same height down a rough inclined plane inclined at an angle 45° to the horizontal, it reaches the ground with a speed v/3. The coefficient of sliding friction between the box and the plane is (acceleration due to gravity is 10 m/s–2 )
(A) 8/9
(B) 1/9
(C) 2/3
(D) 1/3
