A sphere `S` rolls without slipping with a constant speed on a plank `P`. The friction between the upper surface of `P` and the sphere is sufficient to prevent slipping, while the lower surface of `P` is smooth and rest on the ground. Initially `P` is fixed on the ground by a pin `N`. If `N` is suddenly removed
A. S will begin to slip on P
B. P will begin to move backwards
C. the speed of S will decrease and its angular velocity will increase
D. there will be no change in the motion of S and P will still be at rest
