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': 'An increase in kVp increases the : \nSelect and explain. \nA. Number of photons generated, B. Their mean energy, C. Their maximal energy, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Increasing the kVp of an x-ray machine increases:\n\nThe number of photons generated.\nThe mean energy of the photons.\nThe maximal energy of the photons.\n\nRef:Ref: Oral Radiology, Principles and Interpretation / Stuart C. White, Michael J. Pharoah - 7th ed - pg - 10', 'role': 'assistant'}]