A point mass M is released from rest and slides down a spherical bowl (of radius R) from a height H as shown in the figure below. The surface of the bowl is smooth (no friction). The velocity of the mass at the bottom of the bowl is
(a) $\sqrt{gh}$ 
(b) $\sqrt{2gR}$ 
(c) $\sqrt{2gH}$
(d) 0