Question

they like to sing.
nos gusta cantar.
me gusta cantar.
les gusta cantar.
te gusta cantar.

Explanation:

To translate "They like to sing" to Spanish, we use the structure "gustar" with the indirect object pronoun for "them" (les). "Nos gusta cantar" means "We like to sing", "Me gusta cantar" means "I like to sing", "Te gusta cantar" means "You like to sing", and "Les gusta cantar" means "They like to sing".

Answer:

C. Les gusta cantar