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': 'In a patient suffering from chronic myeloid leukemia, Hb falls from 11g% to 4g% in a short span of time, and splenomegaly occurs. The cause could be -a) Accelerated phaseb) CML in blast crisisc) Ineffective erythropoiesisd) Myelofibrosis \nSelect and explain. \nA. ac, B. a, C. ab, D. bc', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]