A solid cylinder is attached to a horizonatal massless spring as shwn in figure.If the cyclinder rolls without slipping, the time period of oscillation of the cyclinder is
A. `2pisqrt(x/g)`
B. `2pisqrt(2M)/(3K)`
C. `2pisqrt(3M)/(8K)`
D. `2pisqrt(3M)/(2K)`