Final answer:
The preterit tense of 'mirar' in the 'vosotros' form is 'Mirasteis'.
Step-by-step explanation:
The preterit tense of 'mirar' in the 'vosotros' form is B. Mirasteis.
The preterit tense is used in Spanish to express completed actions in the past. The 'vosotros' form is used to refer to a group of people in Spain, similar to the English 'you all' or 'y'all' form.
For example, if you want to say 'you all looked' in Spanish, you would say 'vosotros mirasteis'.
Learn more about Spanish verb conjugation