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: Pathology
[{'content': 'Confirmation of myelofibrosis is by ? \nSelect and explain. \nA. Bone marrow aspiration, B. Peripheral smear, C. Leuocytes alkaline, D. Bone marrow biopsy', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is `d' i.e., Bone marrow biopsy Bone marrow biopsy is essential for diagnosis", 'role': 'assistant'}]