Answer: D. Britain asked for help to stop the spread of communism in Turkey and Greece.
Explanation: The United States developed and used the Truman Doctrine after WWII because Britain asked for help to stop the spread of communism in Turkey and Greece. The doctrine stated that the United States would provide military and economic aid to any country threatened by communism. The goal was to contain the spread of communism and prevent its expansion into new countries. The Truman Doctrine was a key part of U.S. foreign policy during the Cold War, and it set the stage for further U.S. involvement in the conflicts in Korea and Vietnam.