is2A wedge of mass M fitted with a spring of stiftness k is kept on a smoth hrizontal surface. A rod of mass m is kept on the wedge as shown in the figure. System is in equilibrium. Assuming that all the surfaces are smooth, the potential energy stored in the spring:
a) mg2tan2θ/2k b) m2g tan2θ/2k c) m2g2tan2θ/2k d) m2g2tan2θ/k