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: Forensic Medicine
Brown discolouration of the mucosa of the stomach is seen in poisoning due to : 
Select and explain. 
A. Nitric acid, B. Sulphuric acid, C. Hydrochloric acid, D. Mercury
B: Sulphuric acid
Answer: B: Sulphuric acid 
Explanation: B i.e. H2SO4