Final answer:
The correct verb form to fill in the blank is 'vas'.
Step-by-step explanation:
The correct verb form to fill in the blank is B. vas.
When addressing two people using the pronouns 'tú y yo' (you and I), the verb form used is the second person singular, which is 'vas' in Spanish.
For example, in the sentence 'Tú y yo vamos a la cafetería para comer', the correct verb 'vas' agrees with the subject 'tú y yo'.
Learn more about Spanish verb forms