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 –G Mm(1/`r_2` – 1/`r_1`) is more/less accurate than the formula mg(`r_2 – r_1`) for the difference of potential energy between two points `r_2` and `r_1` distance away from the centre of the earth.