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': 'Atomic weight is equal to total number of: \nSelect and explain. \nA. Protons, B. Protons and neutrons, C. Protons and electrons, D. Protons, neutrons and electrons', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Protons, neutrons and electrons', 'role': 'assistant'}]