Best move for black ?

Good evening,

In this position : http://en.lichess.org/analysis/rnbqk1nr/pppp1ppp/8/4N3/4P3/8/PPPP1KPP/RNBQ1B1R_b_kq_-

Who can tell me what is the best move for black ?
Black gave the bishop.

Thanks !
EchoIsON

Black has nothing .
it isnt winning a piece back

First impression from an amateur player:
( if this is an ongoing game, please do not read )

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Black knigh to f6 ..

White have an exposed king. Will he send the queen forward ?

The white knight on e5 is not an immediate treat, alone ..
- be prepared. Challenging position, but why impossible ?

:- )

Playing chess for fun and learning