According to the third law of motion when we push an object, the object pushes us back with an equal and opposite force. These two forces are called as action-reaction pair.
The student’s justification is incorrect since action and reaction always operate on different bodies and hence cannot cancel each other. When two equal and opposite forces act on the same body, they cancel each other.
A truck parked on the side of the road has a heavy weight and generates greater friction between the tyres and the ground than the force applied. As a result, the truck will only move if a force greater than the friction force is applied to it.