Who suggested to ‘American policy –makers to “Exercise self – restraint while achieving national interest”?

Correct option is D

The correct answer is George Kennan.
Explanation:
George Kennan, a prominent American diplomat and historian, is widely known for his advocacy of "self-restraint" in U.S. foreign policy, particularly during the early years of the Cold War. Kennan, the architect of the policy of containment towards the Soviet Union, emphasized the importance of exercising restraint while pursuing national interests. His famous "Long Telegram" (1946) and subsequent writings, including his article in Foreign Affairs in 1947 ("The Sources of Soviet Conduct"), urged American policymakers to avoid excessive aggression and to focus on strategic, measured responses to Soviet actions.
Kennan's philosophy was centered around the idea that the U.S. should not seek to overextend itself or engage in unnecessary military interventions. Instead, he argued that the United States should carefully manage its resources, avoid military adventurism, and use its diplomatic influence to counter Soviet expansionism through non-military means wherever possible. This approach to self-restraint was fundamental to the early stages of Cold War diplomacy and is seen as a hallmark of Kennan's intellectual legacy.