This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fundamentals in Radiology, Subject name: Radiology
[{'content': 'Which of the following is the most penetration beam \nSelect and explain. \nA. Electron beam, B. 8 MeV Photons, C. 18 MeV Photons, D. Proton beam', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Penetration power of photons depends on the kinetic energy. higher the kinetic energy of the photon beam,higher will be the penetration power. kVp determines the penetrating power of Xrays.', 'role': 'assistant'}]