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
An increase in kVp increases the : 
Select and explain. 
A. Number of photons generated, B. Their mean energy, C. Their maximal energy, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Increasing the kVp of an x-ray machine increases:

The number of photons generated.
The mean energy of the photons.
The maximal energy of the photons.

Ref:Ref: Oral Radiology, Principles and Interpretation / Stuart C. White, Michael J. Pharoah - 7th ed - pg - 10