Lasting about 45 years, from 1945 (the end of World War II) until the fall of the Soviet Union in 1991. This was a period of highest tensions between the Western bloc countries (primarily the United States) and the Eastern bloc (mainly the U.S.S.R. and states controlled by the Soviet Union). It was initially a political stand-off, but escalated. The two main actors sought to set up zones of control that included countries within their geographic reach. The correct answer is B.