Answer:
Option B
Explanation:
By energy conservation
(K.E)i + (P.E)i = (K.E)f+ (P.E)f
(K.E)i =0,(P.E)i = mgh, (P.E)f = 0
(K.E)f = $\frac{1}{2}I\omega^{2} + \frac{1}{2}mv^{2}$
For the solid cylinder, the moment of inertia,
I = $\frac{1}{2}mR^{2}$
So, mgh =
$\frac{1}{2}(\frac{1}{2}mR^{2})(\frac{v^{2}}{R^{2}})+\frac{1}{2}mv^{2}$
v = $\sqrt{\frac{4gh}{3}}$