Afailure of the red-sensitive nerves in the eye to respond to light properly causes
a. astigmatism.
b. color blindness.
c. chromatic aberration.
d. farsightedness.

When our red-sensitive nerves in our eyes cannot respond to light properly this will result in color blindness - b. 

When either of the three light-sensitive nerves in our nerve tracts; either green, red or blue, we become to color blind for a certain spectrum of light from nature. 

Ibelieve the answer is a-broad because that is a leafed plant.

I'm soooo sorry but i can't answer but you can ask another professor