Two blocks of masses m and M, (M > m), are placed on a frictionless table as shown in figure. A massless spring with spring constant k is attached with the lower block. If the system is slightly displaced and released then (μ = coefficient of friction between the two blocks)

(A) The time period of small oscillation of the two blocks is T = 2π √((m+M)/k)
(B) The acceleration of the blocks is a = kx/(M+m) (x = displacement of the blocks from the mean position)
(C) The magnitude of the frictional force on the upper block is (mμ|x|)/(M+m)
(D) The maximum amplitude of the upper block, if it does not slip, is μ(M+m)g/k
(E) Maximum frictional force can be μ(M + m)g.

Choose the correct answer from the options given below :

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