In our model of an efficient-contracting union (i.e., one that maximizes union profit), the equilibrium is at the Group of answer choices intersection of the firm's iso-profit curve and the union's iso-profit curve the tangency of one of the firm's iso-profit curves to one of the union's iso-profit curves the tangency of the labor demand curve to one of the union's iso-profit curves the intersection of the labor demand curve and the union's iso-profit curve