Answer:
d. Focus its foreign policy on containing the spread of Soviet communism
Step-by-step explanation:
In an influential 1947 article, diplomat George F. Kennan advocated that the US should: "Focus its foreign policy on containing the spread of Soviet communism."
In the article which was titled the "X-Article" and published in a journal named Foreign Affairs George F. Kennan described that "The main element of any United States policy toward the Soviet Union, must be that of a long-term, patient but firm and vigilant containment of Russian expansive tendencies.”