This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Poisoning, Subject name: Forensic Medicine
Brown coloured urine is seen in which poisoning 
Select and explain. 
A. Nitric acid, B. Carbolic acid, C. Sulphuric acid, D. Hydrochloric acid
A: Nitric acid
Answer: A: Nitric acid 
Explanation: color of urine in different poisoning carbolic acid-green Nitric acid- brown Barbiturates - liquid gold Ref: Dr. Bhatia Medical Toxicology