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: Surgery
[{'content': 'A patient has hypocalcaemia which was the result of a surgical complication. Which operation could it possibly have been - \nSelect and explain. \nA. Nephrectomy, B. Thyroidectomy, C. Gastrectomy, D. Vocal cord tumour biopsy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]