If you are going to do something, which infinitive expression do you use?
a) acabar de
b) ir a
c) tener que

The right answer is, C. Tener que.

Explanation:

Because when we speak in the first person and we are going to carry out some activity or commitment, to report that we have something to do we use the expression "Tengo que".

example, I have to do the dishes before going to play.

* Tengo que lavar los platos antes de ir a jugar.