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 results due to deposition of - 
Select and explain. 
A. Copper, B. Iron, C. Silver, D. Urochrome
D: Urochrome
Answer: D: Urochrome 
Explanation: In nuclear senile cataract, there may or may not be associated with deposition of pigment urochrome and/or melanin derived from amino acids in the lens.
Commonly observed pigmented nuclear cataracts are amber, brown (cataract brunescens) or black (cataract nigra) and rarely reddish(cataract Rubra) in colour.