A particle of mass M is at a distance ‘R’ from the surface of a thin spherical shell of mass M uniformly distributed over its surface, R is the radius of the shell. Now select the correct option.

Gravitational potential at the centre is zero but gravitational field is not zero.

At any point inside the shell only gravitational field is zero. 

Neither gravitational field nor gravitational potential is zero inside the shell.

Gravitational field and potential both are zero at the centre of the shell.