Segment AB is on the line y − 3 = 2(x + 2), and segment CD is on the line y − 3 = negative one half(x + 2). Which statement proves the relationship of segments AB and CD?

A. They are parallel because they have the same slope of 2.
B. They are parallel because they have the same slope of negative one half.
C. They are perpendicular because they have slopes that are opposite reciprocals of 2 and negative one half.
D. They are perpendicular because they have slopes that are opposite reciprocals of −2 and one half.