This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Retina, Subject name: Ophthalmology
Distance of macula from optic disc is: 
Select and explain. 
A. 1 mm, B. 2 mm, C. 2.5 mm, D. 4 mm
D: 4 mm
Answer: D: 4 mm 
Explanation: None