The Cold War development that was most likely inspired by the ideas expressed in the passage is (B.) the execution of the Berlin Airlift.
The Berlin Airlift was executed on June 24, 1948, that is to say a year after this presidential message was sent, and it consisted in airlifting supplies such as food, water and medicines to people in West Berlin as a solution to the Soviet blockade of land routes since, at that time, West Berlin was occupied by Soviets. The US president that ordered the Berlin Airlift was Harry S. Truman who sought to keep the hope of West Berlin citizens alive despite adversity. In this sense, this Cold War development is closely related to this presidential message of 1947, which was part of the Truman Doctrine.