Answer:
The correct answer is "same; 50 N".
Step-by-step explanation:
The magnitude of the action force is the same as the magnitude of the reaction force. According to Newton's third law, "for every action force, there exists a reaction force, equal in magnitude and opposite in direction". This applies to any action performed in standard conditions. This the case of a person pushing a chair, if a person pushes a chair with a force of 50 N, then the chair is pushing back with a magnitude of 50 N.