There is friction between M and ground and $\;(\mu_{s}=0.5)\;$ . There is no friction between m and ground . Find the maximum amplitude of S.H.M with which the block m vibrates so that the block M does not move ? $\;(g=10 m/s^2)$

Question

$(a)\;33.3\qquad(b)\;66.7\qquad(c)\;54.9\qquad(d)\;None\;of\;these$