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
In medical radiotherapy linear particle accelerator emits 
Select and explain. 
A. Electron and photons, B. Electron and positrons, C. Neutrons and positrons, D. Neutrons only
A: Electron and photons
Answer: A: Electron and photons 
Explanation: None