What year marked the beginning of the Korean War?

The Korean War began in 1950, making this the correct choice. The conflict started on June 25, 1950, when North Korea invaded South Korea, leading to a military response from United Nations forces, predominantly led by the United States. This event marked a significant escalation in tensions in the region, rooted in the division of Korea following World War II and the subsequent Cold War dynamics. Understanding that 1945 is significant in the context of World War II's end and the division of Korea along the 38th parallel, it does not mark the start of the conflict. The years 1960 and 1970 are well after the war started and do not pertain to the conflict's initiation. Thus, 1950 is the key year that signifies the outbreak of the Korean War from a historical standpoint.