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 _. Your answer should be chosen from the given text, and should not contain other words.

Sydney Bristow: Sloane 's here .
Kelly Peyton: Of course , you did n't ' think we 'd dispose of him this soon , did you ?
Arvin Sloane: I hear your mission was a success . I suppose I should offer you congratulations .
Sydney Bristow: Thank you .
Arvin Sloane: Did you encounter any complications .
Sydney Bristow: Just _ one _ ; but I 've dealt with her once and for all . We should celebrate Arvin . Sydney Bristow is dead .
complications