Newton's Third Law Identifies Mutual Gravitational Pairs Steps:

• Recall Newton's third law: Every action force has an equal, opposite reaction force between the same two interacting bodies.
• Gravitational forces are always mutual: Body A pulls Body B with the same magnitude as Body B pulls Body A, but in opposite directions.
• Action-reaction pairs act on different bodies involved in the same interaction.
• Not enough information: Specific descriptions of forces P, Q, R, and S are missing, preventing identification of the pair. Why B is correct:
• Stated as correct, but cannot confirm without force details tying P and R as mutual attractions between identical bodies per Newton's third law. Why the others are wrong:
• A: P and Q lack descriptions to verify as a pair.
• C: Q and S lack descriptions to verify as a pair.
• D: R and S lack descriptions to verify as a pair.

Final answer: B