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': 'The first-line drug therapy in chronic myeloid leukemia is - \nSelect and explain. \nA. Hydroxycarbamide, B. Alpha-interferon, C. Busulphan, D. Imatinib', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]