The correct answer is A los huéspedos en los balnearios les agradan las criadas y dejan una propina cuando ellos salen del hotel.
Explanation:
In this case we are faced with an indirect object pronoun. These are pronouns used to define to whom or for whom the action of a sentence is addressed.
To identify this type of pronouns we must ask the question to whom? or for whom?
Below I will write what are the indirect object pronoun of Spanish:
they might not like their true self and want to become something else that they think would be who they truly are but others think it isn't so they end up not liking their true self.