AB = x + 15 AD = 2x + 18 BC = 3 - x CD = 3x + 25 Quadrilateral ABCD is a parallelogram if both pairs of opposite sides are congruent. Prove that Quadrilateral ABCD is a parallelogram by finding the value of x. A) x = 3 B) x = -5 C) x = -11 D) x = 11/2