Which direct object pronoun correctly completes this conversation? julián: ¿cómo vas a pagar? ¿tienes la tarjeta de crédito o de debito? rafael: sí, tengo dos?

The answer is las dos

The correct answer is: LAS.

Explanation:

Direct pronoun has to agree with gender and number of the noun. So, as the noun is: cards (debit card and credit card), and that is a feminine plural noun in Spanish,  then, we have to use a direct pronoun that is both feminine and plural too, and that is in Spanish: las.

Remember that in Spanish mostly the termination -a indicates feminine and the termination -s indicates plural.