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 statements is true regarding thyroglobulin? \nSelect and explain. \nA. It is a specific marker for anaplastic carcinoma, B. Elevation after complete therapy suggests recurrence in well-differentiated thyroid malignancies, C. Preoperative elevation always suggests thyroidal disease, D. Intra op estimation from thyroid veins is very useful for prognosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]