What is the strongest move for Black?

Casual Game, https://itsyourturn.com
Analysis of Maddog6 vs. John Coffey

1 2 3 4 5 6 7 8 h g f e d c b a +5

(black to move) 1. e4 e6 2. d4 d5 3. e5 c5 4. c3 Nc6 5. Nf3 Qb6 6. b3 cxd4 7. cxd4 Bb4+ 8. Bd2 Nxd4 9. Bxb4 Qxb4+ 10. Nfd2 Ne7 11. Be2 Nxe2 12. Qxe2 Qd4 13. Nc3 Qxc3 14. O-O Ng6 15. Rfc1 Qxe5 16. Qb5+ Ke7 17. Nf3 Qd6 18. h3 Bd7 19. Qe2 Rhc8 20. Rd1 e5

[ Flip the board | Reset | Options… ] Play online chess

 

Options:
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Pawn promotion:
	- Queen
	- Rook
	- Bishop
	- Knight