Truman Doctrine promised to send aid to all nations threatened by Soviet expansion. The correct option among all the options given in the question is option "B".
The Truman Doctrine actually emerged from a speech in the
month of March of year 1947. Truman in his speech declared that the United
States of America would help any country that would fight against communist
aggression. This policy was also popularly known as the Containment of
Communism. Truman was actually afraid that the communists would take over
several countries and increase their influence.