Based on your description of the graph, the statement that is TRUE is:
The number of troops surged, peaking in 1968, and then declined going into the 1970s.
This aligns with historical data regarding troop levels in the Vietnam War, which saw a significant increase in the mid-1960s, peaking around 1968, followed by a gradual decline in the subsequent years. The other statements do not accurately reflect this trend based on the historical context provided.