Final answer:
The correct verb form is caminan
Step-by-step explanation:
The correct verb form to complete the sentence is caminan.
When addressing a group of people in Spanish, the pronoun 'ustedes' is used, which corresponds to the subject 'you all' or 'you guys' in English. The verb 'caminar' means 'to walk', and the correct form for 'ustedes' is 'caminan'.
For example:
Ustedes caminan a la biblioteca todos los días. (You all walk to the library every day.)
Learn more about Spanish verbs