Answer:
B) Truman Doctrine.
Step-by-step explanation:
It was an American foreign policy proposed by U.S. President Harry Truman. Its purpose was to counter Soviet geopolitical influence. Not by direct military intervention, but by financial aid to support the economy and militaries of the countries involved.
This doctrine leads to the creation of NATO and its often dated by historians as the beginning of the Cold War.
I hope this answer helps you.