Why do humans perceive faint light better in the periphery of the eye?

    a.    Ganglion cells in the periphery transmit their information to a larger brain area.
    b.    The fovea is closer to the retina's blind spot than peripheral receptors are.
    c.    Receptors in the periphery are closer to the pupil.
    *d.    More receptors in the periphery than in the fovea funnel input to each ganglion cell.