The correct answer is B. The event that began the Korean War was a military aggression by a communist nation.
Explanation:
After the end of World War II, the United States and the Soviet Union agreed to divide Korea in two. They drew the border in parallel 38, leaving the North in charge of the Soviet Union and the South in charge of the United States. Each superpower controlled in its respective area the constitution of two new states that remained under their corresponding orbits: the Democratic People's Republic of Korea in the north and the Republic of Korea in the south.
Although negotiations were held for the reunification of Korea in the months before the war, tension intensified with cross-border skirmishes and incursions in parallel 38. The escalation of tension degenerated into an open war when North Korea invaded South Korea on June 25th, 1950.
