Question

1) Which of the following signaled that the Vietnam War would not end quickly?

Answer 1

I am pretty agree with your answers except the first one. As you know Ten Offensive was one of the, or even the hugest military campaigns during Vietnam War that controlled everything throughout South Vietnam, so this is the point.
1. Ten Offensive
2.Credibility gap
3. His popularity was low because of the Vietnam War

Answer 2

The one that signalled vietnam war would not end quickly is : A, Ten offensive.
The difference between what president johnson said and what many journalist reported was called the : C. Credibility gap, and the reason why president johnson decide not to run for president in 1968 was :A. because his popularity was low because of the vietnam war

hope this helps