Acceleration due to gravity is independent of mass of the earth/mass of the body.

Explanation

(a) Acceleration due to gravity at height h `g(h) = g (1-(2h)/R)`  hence according to this acceleration due to gravity decreases as height increases.
(b) Acceleration due to gravity at depth d `g(d) = g(1-d/R)` hence according to this acceleration due to gravity decreases as depth increases.
(c) Acceleration due to gravity `g=(GM_E)/(R^2)` where `M_E` Me mass of earth, hence acceleration due to gravity g is independent to the mass of body (m).
(d) Formula -GMm `(1/r_1 -1/r_2)` is more accurate than the formula `mg(r_1-r_2)`.