The Vietnam War was a conflict during the Cold War in which the United States backed South Vietnam against the North.

• A. Yellow Journalism
• B. Vietnam War
• C. Westward Expansion
• D. Warsaw Pact

Answer: (B)

Recognizing a named historical event from its description. The description points to a Cold War-era conflict in which the United States supported South Vietnam against the North, which is the Vietnam War. In that struggle, the U.S. aimed to halt the spread of communism in Southeast Asia, backing the anti-communist South while the North was aided by communist allies. The other terms refer to different things: Yellow Journalism means sensationalist news reporting from the late 19th century, Westward Expansion is about 19th-century American expansion across the continent, and the Warsaw Pact was a Cold War military alliance, not a conflict name.