This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Radiotherapy, Subject name: Radiology
[{'content': 'Most common cancer worldwide is \nSelect and explain. \nA. Breast cancer, B. Lung cancer, C. Cervical cancer, D. Leukemia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Lung cancer is the most common cancer and the most common cause of cancer death in the world.Reference: Harrison; 19th edition', 'role': 'assistant'}]