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
Thickness of the adult crystalline lens is about: 
Select and explain. 
A. 2.5 mm, B. 3.5 mm, C. 4.25 mm, D. 5 mm
D: 5 mm
Answer: D: 5 mm 
Explanation: Ans. 5 mm