A block of mass `M` is tied to one end of a massless rope the other end of the rope is in the hands of a man of mass `2M` as shown in the figure. The block and the man are resting on a rough plank of mass `M` as shown in the figure. The whole system is resting on a smooth horizontal surface. The man pulls the rope. Pulley is massless and frictionless. What is the displacement of the plank when the block meets the pulley ( Man does not leave his position on plank during the pull)

Options

A. 0.5 m
B. 1 m
C. `2/3` m
D. zero