A tunnel is excavated along the diameter of the Earth. The acceleration of a particle of mass 'm' due to gravity is g' when this particle is at a distance 'x' from the centre of Earth. Then the force 'F' it experiences will be-
1
F ∝ x
2
F ∝ m
3
F' ∝ x-1 g-1
4
F' ∝ m-1 g'