A block with mass (M) is connected by a massless spring with stiffness constant (k) to a rigid wall and moves without friction on a horizontal surface. The block oscillates with small amplitude A about an equilibrium position (x_0). Consider two cases : (i) when the block is at (x_0) , and (ii) when the block is at `x = x_0 + A`. In both the cases, a particle with mass m(lt M) is softly placed on the block after which they strick to each other. Which of the following statement (s) is (are) true about the motion after the mass (m) is placed on the mass (M) ?