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: Pharmacology
Dimercaperol is contraindicated in poisoning with- 
Select and explain. 
A. Iron, B. Mercury, C. Gold, D. Silver
A: Iron
Answer: A: Iron 
Explanation: Ans. is `a' i.e., Iron o Dimercaprol is contraindicated in iron and Cadmium Poisoning as Dimercaperol - Fe and Cd complexes are themselves toxic.