This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Forensic Toxicology - Concepts, Statutes, Evidence, and Techniques, Subject name: Forensic Medicine
[{'content': "Chostek s and Trousseau's Signs is seen in which poisoning? \nSelect and explain. \nA. Oxalic acid, B. Strichynine, C. Hydrocyanic acid, D. Arsenic", 'role': 'user'}, {'content': "Answer: A \nExplanation: ANSWER: (A) Oxalic acidREF: Parikh 6th edition page 8.33Chvostek's and Trousseau s Signs is seen in hypocalcemia.Oxalic acid combines with serum calcium to form insoluble calcium oxalate to cause hypocalcemia", 'role': 'assistant'}]