(b) Which lines have a negative slope? (Select all that apply.) O a Ob O c Od De Of (c) Which lines appear parallel? (Select all that apply.) O a and b O b and d O b and f O c and e O c and f O d and e O d and f (d) Which lines appear perpendicular? (Select all that apply.) O a and b O b and d O b and f O c and e O c and f O d and e O d and f Need Help? Read it(a) Which lines have a positive slope? (Select all that apply.) Ob O c Od De Of (b) Which lines have a negative slope? (Select all that apply. ) O a Ob De Of (c) Which lines appear parallel? (Select all that apply.) O a and b