(20 points) Two players have to simultaneously decide how much to contribute to the provision of a public good. If Player 1 contributes x and Player 2 contributes y, then the payoff to Player 1 is 2(x+y+xy)-x² and payoff to Player 2 is 2(x+y+xy)-2y². (a) (10 points) Find and draw the best response functions of both players. (b) (10 points) Find the Nash equilibrium of this game.