When finding the image produced by a lens via ray tracing, it was suggested that you should always draw a ray that goes through the focal point (the focal ray). (In some cases, an extrapolation of the focal ray passes through the focal point.) Which of the following statements gives the most accurate description of this ray? 

(a) The focal ray passes through the center of the lens.
(b) The focal ray always leaves the lens parallel to the axis of the lens.
(c) The focal ray always leaves the object parallel to the axis of the lens.
(d) The focal ray always passes through a virtual image.
(e) There are two focal rays, one for each focal point.