How Did the Cold War Start

How did the Cold War start?

A) It began after World War II when there was a shortage of coal and heating fuel in Europe.
B) It started when the United States established the Truman Doctrine at the end of World War II,which left Eastern European countries "in the cold" by declaring that they would have to defend themselves without U.S.help.-Consider This: The Truman Doctrine was in response to the Cold War.
C) It began after all of Eastern Europe fell under Soviet domination at the end of World War II,which prompted fears that the Soviets would spread communism around the globe.
D) It started when the Truman Doctrine froze all military alliances into their pre-World War II configurations.