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': 'Which of the following is not a feature of reidel thyroiditis \nSelect and explain. \nA. Fibrosing condition, B. Fibrosing condition, C. FNAC is Investigation of choice, D. Associated with retroperitoneal fibrosis.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: In reidel thyroiditis trucut biopsy is taken.', 'role': 'assistant'}]