Why do some historians criticize the united states' decision to send combat troops to vietnam after the gulf of tonkin incident?

a. it is likely that the south vietnamese could have won the war if the united states had remained in an advisory role.

b. evidence suggests that the reported north vietnamese attack on an american naval vessel may never have happened.

c. americans of the era feared that vietnam would turn to communism if left alone, but today's historians do not think that would have happened.

d. the communist party of the united states of america gained dominance at home while the military focused its efforts overseas.