This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Ophthalmology
Human retina consists about 
Select and explain. 
A. 100 million Rods & 5 million Cones, B. 5 million Rods & 100 million Cones, C. 100 million Rods & 100 million Cones, D. 5 million Rods & 5 million Cones
A: 100 million Rods & 5 million Cones
Answer: A: 100 million Rods & 5 million Cones 
Explanation: (A) 100 million Rods & 5 million Cones # Total number of cones in fovea:> Approximately 200,000. There are 17,500 cones/degree> Rod free area is approximately 10 thus there are 17,500 cones in the central rod-free fovea.> Total number of cones in the retina. - 6,400,000> Total number of rods in the retina. - 110,000,000 to 125,000,000> Rod distribution.> Rods peak in density 180 or 5mm out from the center of the fovea in a ring around the fovea at 160,000 rods/mm2> No rods in central 200 pm.> Average 80-100,000 rods/mm2> Rod acuity peak is at 5.20 or 1.5 mm from foveal center where there are 100,000 rods/mm2