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 most common subtype of thyroid cancer is? \nSelect and explain. \nA. Medullary carcinoma, B. Papillary carcinoma, C. Follicular carcinoma, D. Anaplastic carcinoma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Papillary carcinoma is the most common of the thyroid neoplasms and is usually associated with an excellent prognosis, particularly in female patients younger than 40 years.\nAbout 70% to 80% of patients in the United States in whom thyroid carcinoma is newly diagnosed have papillary carcinoma.', 'role': 'assistant'}]