A quadrilateral has vertices A=(0,0), B=(1,3), C=(0,4), and D=(-1,1). Select the explanation that proves ABCD is a parallelogram. Responses Side AB is parallel to side CD because both have slopes of −1. Side AD is parallel to side BC because both have slopes of 3. A quadrilateral with 2 pairs of parallel sides is a parallelogram. Side AB is parallel to side CD because both have slopes of −1. Side AD is parallel to side BC because both have slopes of 3. A quadrilateral with 2 pairs of parallel sides is a parallelogram. Side AB is parallel to side CD because both have slopes of 3. Side AD is parallel to side BC because both have slopes of −1. A quadrilateral with 2 pairs of parallel sides is a parallelogram. Side AB is parallel to side CD because both have slopes of 3. Side AD is parallel to side BC because both have slopes of −1. A quadrilateral with 2 pairs of parallel sides is a parallelogram. Side AB is parallel to side BC because both have slopes of 3. Side AD is parallel to side CD because both have slopes of −1. A quadrilateral with 2 pairs of parallel sides is a parallelogram. Side AB is parallel to side BC because both have slopes of 3. Side AD is parallel to side CD because both have slopes of −1. A quadrilateral with 2 pairs of parallel sides is a parallelogram. Side AB is parallel to side CD because both have slopes of 1/3. Side AD is parallel to side BC because both have slopes of 1. A quadrilateral with 2 pairs of parallel sides is a parallelogram. Side AB is parallel to side CD because both have slopes of 1/3. Side AD is parallel to side BC because both have slopes of 1. A quadrilateral with 2 pairs of parallel sides is a parallelogram.