Can u answer this question on my Spanish hw pls

Select the best translation for the following term or phrase. what did i do? ¿qué es eso? ¿qué puedo hacer? ¿qué quiere decir ? ¿qué hice?

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.

Why are windows so white like white people