A highly rigid cubical block `A` of small mass `M` and side `L` is fixed rigidly on the other cubical block of same dimensions and of modulus of rigidity `eta` such that the lower face of `A` completely covers the upper face of `B`. The lower face of `B` is rigidly held on a horizontal surface . `A` small force `F` is applied perpendicular to one of the side faces of `A`. After the force is withdrawn , block `A` executes faces of `A`. After the force is withdrawn , block `A` exceutes small oscillations , the time period of which is given by

Options

A. `2pisqrt((M eta)/L)`
B. `2pisqrt(L/(M eta))`
C. `2pisqrt((ML)/(eta))`
D. `2pisqrt(M/(egaL))`

Answer

D