Which of the following pairs of lines are perpendicular? Select all that apply.

A. y=2/3x+4 and y=2/3x-8
B. y=2/3x-8 and y=-3/2x-8
C. y=x+2 and y=-x+3
D. y=3x+2 and y=3x-2
E. y=3 and y=4
F. y=4/5x-8 and y=-5/4x+3