Final answer:
The correct answer is 'B. vieron.'
Step-by-step explanation:
The subject of the question is Spanish. The correct answer is B. vieron.
In this sentence, 'nuestros padres' is the subject, which means 'our parents.'
The verb 'vieron' is the correct conjugation of the verb 'ver' (to see) in the past tense. Therefore, the correct sentence is 'Nuestros padres vieron un partido de béisbol ayer.'
Learn more about Conjugation of Spanish verbs