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
Regarding color blindness true-a) Mainly congenitalb) Can be tested with Fansworth 100 hue testc) Ishihara chart test red/ green color blindnessd) Jerlin- Merlin cotton wool tests it 
Select and explain. 
A. abc, B. bc, C. acd, D. bcd
A: abc
Answer: A: abc 
Explanation: Most common type of colour blindness in congenital.
Fansworth munsell 100 hue test is the most sensitive test for both congenital and aquired colour defects.
Ishihara plates mainly used to screen congenital protanopes (red blind) and deutranopes (green blind).