Question

a mí __________ mirar las películas.
me gusta
me gustan
me gusto

Explanation:

In Spanish, the verb gustar agrees with the thing that is liked. Here, the infinitive phrase mirar las películas (to watch movies) functions as a singular noun concept, so we use the singular form gusta. Me gustan is for plural nouns, and me gusto refers to liking oneself, which does not fit the context.

Answer:

me gusta