In the arrangement as shown a mass m is released from rest with spring unstreched.What is the speed of block at equillibrium position

Question

$a)\; v=\sqrt {\large\frac{gm}{k}}\\ b)\;v=g \sqrt {\large\frac{m}{R}} \\ c)\;v=\sqrt {\large\frac{m}{Rg}}\\ d)\;v=\sqrt {\large\frac{mk}{g}}$