In the arrangement shown by what acceleration the boy must go up so that 100 kg block remains stationary on the wedge. The wedge is fixed and friction is absent, every where $(g=10 m/s^2)$

Question

 

\[(a)\;2 m/s^2 \quad (b)\; 6m/s^2 \quad (c)\;4 m/s^2 \quad(d)\;8 m/s^2 \]