Final answer:
The correct form of the verb 'vivir' to fill in the blank in the dialogue is 'Viven'.
Step-by-step explanation:
The correct form to fill in the blank in the dialogue would be Viven.
When asking someone where they live in Spanish, we use the verb vivir (to live). In this case, since the question is directed at multiple people, we use the second person plural form of the verb, which is viven.
Example: ¿Dónde viven Uds.? (Where do you all live?)
Learn more about Spanish verb conjugation