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
Causes of early onset of cataract are all except: 
Select and explain. 
A. Diabetes mellitus, B. Smoking, C. Trauma, D. Recurrent episodes of diarrhoea
B: Smoking
Answer: B: Smoking 
Explanation: Ans. Smoking