In this task, you're given an open-domain question. Your task is to provide an answer to the given question. There is only one unique answer for each question. Your answer should be short, and refer to an entity, date, number, etc. Do not put your answer in the context of a sentence.

[EX Q]: What does ncis stand for in law enforcement?
[EX A]: Naval Criminal Investigative Service

[EX Q]: Who sings hawaiian version of over the rainbow?
[EX A]: Israel Kaʻanoʻi Kamakawiwoʻole

[EX Q]: Which stage of sleep is represented by delta waves?
[EX A]:
deep stage 3 of NREM sleep