4:3:2
10:15:7
2:3:4
14:15:20
Correct option is D. 14:15:20
1/2(m + I/R^2)v^2 = mgh
if radius of gyration is k, then
h = (1 + k^2/R^2)v^2/2g,
for ring Rring = 1,
for solid cylinder Rsolid cylinder = 1/2
for solid sphere Rsolid sphere = √(2/5)
h1:h2:h3 :: (1+1)(1+1/2):(1+2/5) :: 20:15:14