The action and reaction forces act on different objects, therefore the net force is not always zero, so anything can be accelerated.
Answer: A
Explanation
Consider two objects. When one object applies force to another object (which is at a state of rest), this force is known as action force.
Here the force is applied to the second object.
As a reaction to the force, the object gains energy and changes its state of rest to action.
This is reaction force and can be seen in the second object only.
Therefore, both action and reaction take place in different bodies.