Fill in the blank in the following dialogue with the appropriate interrogatory word below.

¿ es el examen?
es el martes.

a. cuándo
b. qué
c. quién
d. cómo

this question is given using the conditional form. conditional tenses are is used when talking about hypothetical situations and probabilities. also, this is used when making polite requests. so comprarías is the conjugation of the verb comprar that matches the second person singular in the conditional. finally:

¿cuál comprarías tú?

usualmente me lavo los dientes antes de acostarme pero ayer no me lavé.  

usualmente hago mis tareas a las 15: 00pm pero ayer las hice a las 20 pm.  

usualmente llego a mi casa a las siete pero ayer volví a las nueve  

usualmente cocino arroz pero ayer cociné fideos.  

usualmente llamo a mi hermano al mediodía pero ayer lo llamé en la noche

corras is the only one that is informal but doesn't follow the suffix rule. correr is the verb. corre is the formal verb form. corra would be used as the formal is corre ended with an a.

your best bet would be corras, it's the only one that is informal but is still wrong