OK, so I'm stealing this from an Arseblog Arsecast Extra from the other week...
If you somehow got hold of a real-life Fifa-style player editor (or whatever it is that the kids are playing these days), and you could boost just 1 stat/attribute for 3 different Arsenal players, who and what would they be?
Obviously 'Mertesacker' and 'pace' is a given, so you now have 2 choices left...