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
All of the following intraocular foreign bodies produce suppurative reaction except: 
Select and explain. 
A. Pure zinc, B. Mercury, C. Copper alloys, D. Nickel
C: Copper alloys
Answer: C: Copper alloys 
Explanation: Ans. Copper alloys