You need to answer a given question containing a blank (_). Your answer must be one of the two objects mentioned in the question, for example "trophy" and "suitcase". Your answer must not contain a word that is not present in the question. Please don't use articles (e.g., the, a) before the answer.
Q: The same material could be learned from books and videos, but most students picked the _ so they could study on the bus.
A: 
books