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
Cataract brunescens result due to deposition of: 
Select and explain. 
A. Melanin, B. Copper, C. Iron, D. Silver
A: Melanin
Answer: A: Melanin 
Explanation: Ans. Melanin