The right answer is b. jugaban
Ellas nunca jugaban con animales de peluche.
jugaban is the right conjugation of the ar verb jugar for the third-person plural in the imperfect tense. The imperfect is used to talk about past actions, conditions, or events that occurred regularly or frequently or that were in progress in a moment in the past. To conjugate a verb in the imperfect, take away the ar ending and add the new ending according to the subject of the sentence. For the third-person singular, the ending is aban.