The centre of mass of an extended body on the surface of the earth and its centre of gravity
(a) are always at the same point for any size of the body.
(b) are always at the same point only for spherical bodies.
(c) can never be at the same point.
(d) is close to each other for objects, say of sizes less than 100 m.
(e) both can change if the object is taken deep inside the earth.
