Select the pair of equations whose graphs are perpendicular.

(Points : 5)

a 5x – 8y = 9

12x – 5y = 7

b x + 6y = 8

y = 2x – 8

c y = 2x – 7

x + 2y = 3

d 2y = –3x + 5

2x + 3y = 4

i think it d im i correct