Final answer:
The verb form to fill in the blank is 'vamos'.
Step-by-step explanation:
The correct verb form to fill in the blank is D. vamos.
The subject of the sentence is 'Mi amigo y yo', which translates to 'My friend and I' in English.
Since the subject is plural ('we'), the correct verb form is 'vamos', which means 'we go'.
Learn more about Spanish verb conjugation