Assuming we are given the formulation of a linear programming (LP) problem. To find the optimal solution of this LP problem, we are using the graphical method. if there is a point on the graph that satisfies all of the constraints at the same time, this point must be: a) An optimal solution point. b) At the intersection of the profit line and a constraint c) A corner point. d) At the intersection of two or more constraints. e) At the intersection of the non-negativity constraints f) None of the above