Choose the correct alternative :
(a) Acceleration due to gravity increases/decreases with increasing altitude.
(b) Acceleration due to gravity increases/decreases with increasing depth (assume the earth to be a sphere of uniform density).
(c) Acceleration due to gravity is independent of mass of the earth/mass of the body.
(d) The formula −GMm(1/r₂−1/r₁) is more/less accurate than the formula mg(r₂−r₁) for the difference of potential energy between two points r₂ and r₁ distance away from the center of the earth.
