This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Tritanopes have defective assessment of whichcolor ? 
Select and explain. 
A. Red, B. Blue, C. Green, D. Yellow
B: Blue
Answer: B: Blue 
Explanation: Ans. is `b' i.e., Blue Colour Defective Absent GreenRedBlue DeuteranomalousProtanomalousTritsnomalous DeuteranoPtaProtanopiaTritanopia