This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Toxicology - 1, Subject name: Forensic Medicine
[{'content': 'Brain is preserved in all of the following, except: \nSelect and explain. \nA. OPC poisoning, B. Alkaloid poisoning, C. Heavy metal poisoning, D. Volatile organic poisoning', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Preservation of additional viscera: (1) Hea: strychnine, digitalis, yellow oleander. (2) Brain: alkaloids, OPC , opiates, CO, cyanide, strychnine, barbiturates; and volatile organic poisons. (3) Spinal cord: strychnine and gelsemium. (4) C.S.F: alcohol (5) Bile: Narcotic drugs, cocaine, methadone, glutathione, barbiturates (6) Vitreous humour: alcohol, chloroform, cocaine. (7) Lung: one lung in gaseous poisons, hydrocyanic acid, alcohol, chloroform, etc. (8) Bone: arsenic, antimony, thallium or radium. (9) Fat: 10 gm from abdominal wall or perinephric region in cases of poisoning by pesticides and insecticides.', 'role': 'assistant'}]