The correct answer is federal troops.
President Kennedy sent federal troops to the universities of Alabama and Mississippi in 1963.
The situation in the University of Alabama and the University of Mississippi was tense. Racism in those places prohibited black students to enter the universities. President Kennedy sent the troops to resolve the situations. Indeed, Kennedy sent the Alabama National Guard to the Alabama campus, and Federal Troops to the University of Mississippi to control a protest of students who did not want blacks on campus.