On a coordinate plane, 2 lines are shown. line a b has points (negative 4, negative 2) and (4, 4). line c d has points (0, negative 3) and (4, 0).
which statement best explains the relationship between lines ab and cd?

they are parallel because their slopes are equal.
they are parallel because their slopes are negative reciprocals.
they are not parallel because their slopes are not equal.
they are not parallel because their slopes are negative reciprocals