This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pathology
[{'content': 'Most common Thyroid CA post radiation exposure \nSelect and explain. \nA. Papillary CA, B. Medullary CA, C. Follicular CA, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Papillary Carcinomas are the most common form of thyroid cancer which can occur at any time of life but more oftenly between the ages of 25 and 50 and they are associated with previous exposure to ionizing radiation. Ref: Robbins and cotrans 9e Pg 1095', 'role': 'assistant'}]