Cappelle La Grande 2013 Rd9, GM Hansen E(CAN)

Tournament Site Cappelle-chess 2013
Here is Hansen's clutch last round win with black.
See also Hansen's website hansenchess

Hansen's career has just begun to explode:

• 2011: Tied 1st Canadian Championship
• 2011: Qualified to 2011 World Cup
• 2012: Canadian Open Champion
• 2012: 5th Place World U-20 Championships
• 2012: Tied 1st Pan American Championship
• 2012: Qualified to 2013 World Cup
• 2012: Became member of Canadian National Team and represented Canada at the Olympiad
• 2012: International Grandmaster

GM Hansen,Eric thinking hard at the Panama Open 2012

Vorobiov,E (2584) - Hansen,Eric (2557) 

French vs. King’s Indian Attack[C00]
29th Open Cappelle la Grande FRA (9), 02.03.2013

Position 1

Black's a2 pawn looks vulnerable while white's b,c pawns are ready to roll. What do you suggest for black?

Black to Play

20.b4