Look at the attached image!​

Prefer it or imperfect: una noche yo (mirar) a in fantasma en casa de mis abuelos

When could you attach the direct object pronoun to an infinitive verb? a: when an infinitive verb follows a conjugated verb. b: when an infinitive verb ends in a question. c: when a stem-changing verb ends in a question. d: when a stem-changing verb follows a conjugated verb.

El padre regaló un coche a su hijo, pablo.