Inside a uniform spherical shell (a) the gravitational potential is zero

(b) the gravitational field is zero
(c) the gravitational potential is same everywhere
(d) the gravitational field is same everywhere.

EXPLANATION: 

Inside a uniform spherical shell the gravitational potential is -GM/a every where. Where a = radius of the shell. So (a) is not true but (c) is true. The field is zero and same everywhere inside a shell, so (b) and (d) is true.

(b) the gravitational field is zero
(c) the gravitational potential is same everywhere
(d) the gravitational field is same everywhere.

EXPLANATION: 

Inside a uniform spherical shell the gravitational potential is -GM/a every where. Where a = radius of the shell. So (a) is not true but (c) is true. The field is zero and same everywhere inside a shell, so (b) and (d) is true.