Two blocks each of mass m are joined together using an ideal spring of force constant K and natural length `l_(0)` . The blocks are touching each other when the system is released from rest on a rough horizontal surface. Both the blocks come to rest simultaneously when the extension in the spring is `(l_(0))/4`. The coefficient of friction between each block and the surface (assuming it to be same between any of the blocks and the surface) is :

Options

A. `(Kl_0)/(40mg)`
B. `(Kl_0)/(8mg)`
C. `(3Kl_0)/(8mg)`
D. `(17Kl_0)/(20mg)`

Answer

C