By 1969, the number of US troops in Vietnam was approximately 500,000.
Here's a detailed, step-by-step solution to understand this:
1. Historical Context: During the Vietnam War, the United States gradually increased its military presence to support South Vietnam against the North Vietnamese forces.
2. Escalation of Troops: The number of US troops in Vietnam grew substantially over the years, particularly during the 1960s under President Lyndon B. Johnson’s administration, which escalated the US involvement dramatically.
3. Peak Deployment: By 1969, the US had significantly increased its troop deployment to counter the advancing North Vietnamese forces and to stabilize the situation in South Vietnam. This period saw the highest number of troops on the ground.
4. Quantitative Data: Historical records indicate that by the end of the 1960s, specifically in 1969, the number of US troops stationed in Vietnam reached its peak.
Based on these points, we can conclude that the correct number of US troops in Vietnam by 1969 was 500,000. Thus, the correct choice from the given options is:
500,000.
