Given the task definition and input, reply with output. In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. There are several possible answers, you'll need to choose the proper one. Carefully read the given text, pay special attention to the marked number, think about what (unwritten) information the marked number holds inside, choose the most adequate word(s) from the optional answers. If none of them seems right to you, there's also an option for other. If your answer is "REFERENCE", also write the reference entity, otherwise write the implicit option name. Options to choose from are:
REFERENCE: Some object which is being mentioned in the text before or after the target number. The reference answer has a higher priority than any other. If both Reference and another answer are possible, prioritize the Reference.
YEAR: Describing a calendric year
AGE: Describing someone's age
CURRENCY: Reference to some monetary value e.g dollar, euro etc.
PEOPLE: Describing a single/plural persons
TIME: Describing a time of the day. Usually you can add the word o'clock after those numbers.
OTHER: Some other option, which isn't listed here.

Elliot Stabler:  They could n't publish the killer 's name because of his age , but I 'm telling you , it was the most gruesome murder in Bedford , New Hampshire 's history .
Olivia Benson: We talked to the local police . They said that he was always a psycho . He 's been collared five times for breaking and entering .
Elliot Stabler: His juvenile records were sealed and then expunged when he was released .
Alexandra Cabot: When did he get out ?
Olivia Benson: Three years ago when he was 19 .
Elliot Stabler: He was supposed to be in there till he was _ 21 _ , but he got out early for good behavior .
Olivia Benson: Of course he did because he 's a sociopath . He gets a clean slate , a new name and then he moves here .
Elliot Stabler: Where he kills again .
AGE