Final answer:
The appropriate verb to fill in the blank is 'debemos.'
Step-by-step explanation:
To fill in the blank in the sentence 'Manuel y yo ___ estudiar juntos para el examen del viernes,' we need to use the appropriate verb in the present tense. The correct option is 'C. debemos.' 'Debemos' is the first person plural form of the verb 'deber,' which means 'to have to' or 'to must' in English.
Learn more about verbal conjugation in Spanish