Prove that the polygon with coordinates A(5, 6), B(8, 5), and C(2, -3) is a right triangle. a) slope of CB = slope of AC = 3; perpendicular lines form a right angle ; b) slope of AB = 3; slope of CB =; both have denominators of 3 making the perpendicular c) cannot be proven d) slope of AB = slope of AC = 3; perpendicular lines form a right angle