Definition: 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 _. Your answer should be chosen from the given text, and should not contain other words.
Input: Nathan:  So , do you know what the Turing Test is ?
Caleb: Yeah . I know what the Turing Test is . It 's when a human interacts with a computer and if the human does n't know they 're interacting with a computer , the test is passed .
Nathan: And what does a pass tell us ?
Caleb: That the computer has artificial intelligence . Are you building an AI ?
Nathan: I 've already built _ one _ .

AI