This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid Malignancies, Subject name: Surgery
[{'content': 'In case of a long standing goitre., ca most probable to occur is : \nSelect and explain. \nA. Follicular, B. Papillary, C. Anaplastic, D. Medullary', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. is \'a\' ie follicular "An increased incidence of cancer (usually follicular) has been reported from endemic areas. Dominant or rapidly growing nodules in longstanding goiters should always be subjected to aspiration cytology." - Bailey & Love', 'role': 'assistant'}]