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': 'Use of higher kVp is: \nSelect and explain. \nA. Good for film, B. Bad for patient, C. Bad for film, D. All of the above', 'role': 'user'}, {'content': "Answer: C \nExplanation: Increasing the kVp increases the potential difference between the cathode and the anode, increasing the energy of each electron when it strikes the target. The greater the energy of an electron, the greater the probability it will be converted into X-ray photons. Increasing the kVp of an X-ray machine increases:\n\nThe number of photons generated.\xa0\nThe mean energy of the photons.\xa0\nThe maximal energy of the photons.\n\nAs the kVp of the X-ray beam increases, subject contrast decreases. Similarly, when relatively low kVp energies are used, subject contrast increases. Most clinicians select a kVp in the range of 60 to 80. At higher values, the exposure time is reduced, but the loss of contrast may be objectionable because subtle changes may be obscured.\xa0\nWhite and Pharoah's Oral\xa0 Radiology Principles and Interpretation 8th edition", 'role': 'assistant'}]