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
Rotating anode is mainly used to: 
Select and explain. 
A. Focus photons, B. To avoid heel effect, C. To dissipate heat from focal spot, D. Increase the energy of photons
C: To dissipate heat from focal spot
Answer: C: To dissipate heat from focal spot 
Explanation: None