Select perpendicular lines from the given pair of lines :

Select one:

a.
y = − 3x + 7, y = 3x + 11


b.
y = 3x + 7, y = x / 3 + 11


c.
y = − 3x + 7, y = x / 3 + 11


d.
y = − 3x + 7, y = − x / 3 + 11