C. Newton’s Third Law of Motion.
Because...
Newtons third law implies conversation of momentum it can also be seen as following from the second law: when one object pushes a second object at some point of contact using an applied force, there must be an equation of opposite force from the second object that cancels the applied force. Otherwise, there would be a nonzero net force on a massless point which, by the second law, would accelerate the point of contact by an infinite amount.
