Diplomat George Kennan spent much of his career studying the Soviet Union. Upon the start of the Cold War Kennan informed U.S. leaders that the Soviets were moving "inexorably along the prescribed path, like a persistent toy automobile wound up and headed in a given direction, stopping only when it meets unanswerable force." Therefore, Kennan introduced the. a. Truman Doctrine b. Marshall Plan c. policy of containment d. National Security Act