Action and reaction
A. Always act on two different bodies
B. Are equal in magnitude
C. Act in opposite direction
D. All of the above

Hint: Consider a bullet firing from a gun. When the bullet is fired, an opposite force reacts on the gun also. This gives the concept of the action and reaction. By discussing the above example, we can give the answer to the above question.

Complete step by step answer:
Force on an object can be defined as the push or pull acting on that object due to the interaction of the object with another object.

According to Newton’s third law, every force has an equal and opposite reaction. The force applied on an object can be called the action and the opposing force given by the object is called the reaction.

For example, when we fire a bullet, we apply a force on the bullet through the gun. Due to this force the bullet gains speed. When the bullet is fired, the bullet will also apply an opposite force on the gun. This opposite force on the gun is equal to the force we apply on the bullet. Due to conservation of momentum, the speed of the gun in the backward direction is small. The force we apply on the bullet is called the action and the opposite force applied by the bullet on the gun is called the reaction.

From the above example we get that, the action and reaction acts on two different bodies, both the action and reaction are equal in magnitude and the action and reaction acts in opposite directions.
Hence, the correct answer is option D.

Note:
The action and the reaction force are equal and opposite to each other. So, we can say that both the forces will cancel each other. But this does not happen because the action and the reaction forces act on different bodies.