This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrine, Subject name: Pathology
[{'content': 'Medullary ca of thyroid is associated with increase in \nSelect and explain. \nA. Calcitonin, B. Thyroglobulin, C. T3, D. T4', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Calcitonin(Ref: Robbins 9th/pg 1099-1100)*In Medullary Carcinoma Thyroid, serum Calcitonin is elevated.*Elevated serum calcitonin also provides a marker of residual or recurrent disease.*All patients with Medullary Carcinoma Thyroid*should also be tested for RET mutations, so that genetic counseling and testing of family members can be offered;', 'role': 'assistant'}]