The kinetic energy of partical moving along a circule of radius `R` depends upon the distance covered `S` and given by `K = aS` where `a` is a constant. The the force acting on the partical is
A. `(aS)/( R)`
B. `(2aS^(2))/( R)`
C. `(aS^(2))/( R^(2))`
D. `(2aS)/( R)`