A system of two blocks A and B and a wedge C are released from rest as shown in figure. Masses of the blocks and the wedge are $m,2m \;and \;2m$ respectively. The displacement of the wedge C when the block slides down the plane a distance 10 cm is (neglect friction)

Question

$$\begin {array} {1 1} (a)\;5 \sqrt 2\;cm & \quad (b)\;4\;cm \\ (c)\;3 \sqrt 2\;cm & \quad  (d)\;\frac{5}{\sqrt 2}\;cm \end {array}$$