Q1. A colour-blind person is unable to discriminate between:
A Red and yellow colour
B Blue and red colour
C Red and green colour Correct
D Blue and green colour
Explanation
The most common form of colour blindness is red-green colour blindness. In it, a person has difficulty distinguishing red from green because the cone cells responsible for these colour signals do not function normally. Red and yellow, blue and red, and blue and green can also cause confusion in some rare or severe visual defects, but they are not the standard pair tested in basic biology questions on colour blindness. Therefore, the expected CET answer is the inability to discriminate between red and green colours.