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]: She wondered if the schedules or the classes would lead to the most discipline, but the _ had the most effect.
[A]: classes


[Q]: The bag was used to collect some water and emptied to the pot but to out disappointment we met nothing in the pot. The _ is  watertight.
[A]: bag


[Q]: After the break we faxed over the single paper but not the whole document since the _ was long.
[A]:
document