Final answer:
The correct direct object pronoun to complete the conversation is 'la'.
Step-by-step explanation:
The correct direct object pronoun to complete the conversation is la.
Julián asks Rafael how he is going to pay, and Rafael responds by saying, "Yes, I have it." In this context, "la" is the direct object pronoun that refers to the credit card (tarjeta de crédito).
So, the correct option is OB. la.
Learn more about Direct object pronouns in Spanish