As shown in figure, a block of mass m is projected from wall A with velocity $$2v_0$$ on the rough surface with constant sliding friction to hit the wall B with velocity $$v_0$$. With what velocity same mass m should be projected to hit the wall B with same velocity $$v_0$$ if the surface is now moving upward with an acceleration of a = 4g ?

A

$$2v_0$$

B

$$3v_0$$

C

$$4v_0$$

D

$$5v_0$$