When a net force acts on an object, the object will be accelerated in the direction of force with an acceleration proportional to:
A. the force on the object
B. the velocity of the object
C. the mass of the object
D. the inertia of the object.

Hint: In this question we have been asked that would be the acceleration of an object proportional to, when the object is accelerated in the direction of the force due to the force applied. Now, we know that Newton’s second law deals with objects moving due to constant acceleration by the force applied. Therefore, we shall be discussing the same to answer our question.
Formula used:
\[F=ma\]

Complete answer:
 We know that, for a constant mass m the Newton’s second law can be given as,
\[F=m\dfrac{dV}{dt}\]
We know that the rate of change of velocity is the acceleration.
Therefore,
\[F=ma\]
Now, according to Newton's second law, we know that when a net force is applied on an object the object will move in the direction of the force. And as the equation of second law states the acceleration of the would be proportional to the net force applied on the object.

So, the correct answer is “Option A”.

Note:
The foundation of classical mechanics was done by Sir Isaac Newton when he introduced the laws of motion. The laws of motion describe the relationship between mass of a body and the forces acting on it. And also, the reaction of objects to these forces. Newton postulated three different laws to describe the motion of a particle.