Final answer:
The appropriate indirect object pronoun for the given sentence is "nos."
Step-by-step explanation:
Based on the sentence given, the appropriate indirect object pronoun to fill in the blank is nos.
The sentence "Ella trae un perro a nosotros" translates to "She brings a dog to us." Here, "us" is the indirect object, and in Spanish, the indirect object pronoun for "us" is "nos." So the sentence would be "Ella nos trae un perro."
Learn more about Spanish pronouns