On a large tray of mass M an ice cube of mass m, edge L is kept. If the ice melts completely , the COM of the system comes down by

Question

$$\begin {array} {1 1} (a)\;\frac{mL}{2(M+m)} \\ (b)\;\frac{(M-m)L}{2(M+m)} \\ (c)\;\frac{(M+2m)L}{2(M+m)} \\ (d)\;\frac{2ML}{(M+m)} \end {array}$$