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
[{'content': 'In chronic arsenic poisoning the following samples can be sent for laboratory examination, except - \nSelect and explain. \nA. Nail clipping, B. Hair samples, C. Bone biopsy, D. Blood sample', 'role': 'user'}, {'content': "Answer: D \nExplanation: Arsenic is rapidly cleared from blood.so a blood sample is only useful for acute poisoning Ref: K.S.Narayan Reddy's Synopsis of Forensic Medicine and Toxicology, 29th edition, Chapter 26, page 295.", 'role': 'assistant'}]