This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lens, Subject name: Ophthalmology
Commonest cause of cataract- 
Select and explain. 
A. Hereditary, B. DM, C. Trauma, D. Age related
D: Age related
Answer: D: Age related 
Explanation: Most common type of cataract is senile (age related) cataract. Ref: Ophthalmology by Duker's 2nd/e p.420.