This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Toxicology - 3, Subject name: Forensic Medicine
[{'content': 'Bluish discoloration of gastric mucosa seen in which poisoning? \nSelect and explain. \nA. Mercury, B. Cadmium, C. Amytal sodium, D. Arsenic', 'role': 'user'}, {'content': 'Answer: C \nExplanation: POISONS STOMACH MUCOSA Carbolic acid Leathery mucosa Sulphuric acid Black necrotic stomach mucosa Arsenic Red velvety Mucosa Mercury Slate gray Mucosa HNO3 Yellowish Sodium amytal,Copper sulfate Blue', 'role': 'assistant'}]