Complete Color Blindness Results in a Perception of the World

Multiple Choice

Complete color blindness results in a perception of the world only in shades of black and white and is caused by

A) cones that are missing or function abnormally.
B) rods that fail to function under higher levels of illumination.
C) excessive pigmentation of the cornea.
D) a lens that has lost its elasticity and can no longer focus the image appropriately on the retina.