Answer:
b. authorized the president to take any measures necessary to repel attacks against United States forces and allies in Southeast Asia.
Step-by-step explanation:
The United States government declared the Gulf of Tonkin Resolution in 1964 with having support from President Johnson to use action for defending US troops stationed in Asia (Vietnam). According to him, steps needed to check the assurance of peace in Southeast Asia. The decision declared after North Vietnam attacked a US warship stationed in the Gulf of Tonkin.