Answer:
This problem stands for indirect object pronouns. An Indirect Object Pronoun is a person that, in indirect way, takes the action of a verb. So this tells us to whom or for whom an action is done.
1. El vendedor les dice el precio a los clientes.
Here the action is being performed for los clientes, therefore we use les which is the indirect object pronoun that matches the third person plural.
2. Ahora mismo mi mamá está en una tienda. Me un mensaje electrónico para saber si quiero una bolsa nueva.
Here the action is being performed for me, therefore we use me which is the indirect object pronoun that matches the first person singular.
3. ¿Tus amigos te dan muchos regalos en tu cumpleaños? le dan te dan le piden te piden
Here the action is being performed for you, therefore we use te which is the indirect object pronoun that matches the second person singular (informal form).
4. La dependienta le compra una falda verde a Cristina.
Here the action is being performed for Cristina, therefore we use le which is the indirect object pronoun that matches the third person singular.
5. Los muchachos nos describen el nuevo centro comercial a Roberto y a mí.
Here the action is being performed for us, therefore we use nos which is the indirect object pronoun that matches the first person plural.
6. ¿María siempre le paga a usted con tarjeta de crédito?
Here the action is being performed for you (formal form), therefore we use le which is the indirect object pronoun that matches the second person singular (formal form).