A body of mass M is kept n a rough horizontal surfasce (friction coefficient `=mu`). A person is trying to pull he body by applying a horizontal force but the body is not moving. The force by the surface on A is F, where
A. `F = mg`
B. `Mg le F le Mg sqrt(1+mu^(2))`
C. `F = mu Mg`
D. `Mg ge F ge Mg sqrt(1-mu^(2))`
