The force applied on a stationary body varies directly with the acceleration with which it starts to move. If a force of 10 N is applied on a stationary body, it starts to move with an acceleration of 2 m/`sec^(2)`. Find the force (in N) to be applied on the body at which starts to move with an acceleration of 4 m/` sec^(2)`.
A. 30
B. 20
C. 40
D. 50
