Final answer:
The appropriate indirect object pronoun to fill in the blank is "le" in Spanish.
Step-by-step explanation:
In the sentence "Él quiere más agua._____ trae usted más agua, por favor?", the appropriate indirect object pronoun is le. So the correct answer is A. If we fill in the blank with "le", the sentence would read: "Él quiere más agua. Le trae usted más agua, por favor?". In this sentence, the indirect object pronoun "le" is used to mean "him" or "her". It indicates that he wants more water brought to someone (him or her).
Learn more about Indirect Object Pronoun in Spanish