`A` mass `M` is suspended from a light spring. An additional mass `m` added to it displaces the spring further by distance `x` then its time period is
A. `T=2pisqrt((mg)/(x(M+m)))`
B. `T=2pisqrt(((M+m)x)/(mg))`
C. `T=(pi)/(2)sqrt((m)/(x(M+m)))`
D. `T=2pisqrt((M+m)/(mgx))`
