The pulley arrangements shown in figure are identical, the mass of the rope being negligible. in case I, the mass m is lifted by attaching a mass 2m to the other end of the rope. In case II, the mass m is lifted by pulling the other end of the rope with a constant downward force F = 2mg, where g is acceleration due to gravity. The acceleration of mass m in case I is

Zero
More then that in case II
Less than that in case II
Equal to that in case II