Three planets of same density have radii R1, R2 and R3 such that R1 = 2R2 = 3R3. The gravitational field at their respective surface are g1, g2 and g3 and escape velocities from their surfaces are v1, v2 and v3, then
(a) g1/g2 = 2
(b) g1/g3 = 3
(c) v1/v2 = 1/4
(d) v1/v3 = 3
