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: Radiology
[{'content': 'Cranial Irradiation" is given for: \nSelect and explain. \nA. Small cell cancer, B. Squamous cell cancer, C. Anaplastic cancer, D. Adenocarcinoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Small cell cancer', 'role': 'assistant'}]