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: Medicine
[{'content': 'A pt. being investigated for anemia has a dry marrow tap ; peripheral smear reveals tear drop cells, likely diagnosis is : \nSelect and explain. \nA. Leukemia, B. Lymphoma, C. Myelofibrosis, D. Polycythemia rubra vera', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]