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': 'About X-rays which is/are not true \nSelect and explain. \nA. Long wavelength, B. Low frequency, C. Dual character, D. Penetrating', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]