Which pair of equations are perpendicular lines? A. 5x + 2y = 9 and y = –5/2x+27/2 B. x – 3y = 11 and y = –3x + 23 C. 4x + 2y = 6 and y = –2x + 18 D. x – 3y = 5 and y = 3x – 1