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': 'In a patient having dense bones, penetration is best\nachieved by: \nSelect and explain. \nA. Increase in mA, B. Increase in kVp, C. Increased exposure time, D. Increased developing time', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]