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
All of the following factors increases the density of X-ray except: 
Select and explain. 
A. Increasing the kVp, B. Reducing the distance between focal spot and film, C. Decreasing the mA, D. None of the above
C: Decreasing the mA
Answer: C: Decreasing the mA 
Explanation: Factors that increase the density of X-ray:

Increasing the mA, KVp or exposure time increases the density.
Reducing the distance between focal spot and films also increases film density.
Density is inversely proportional to subject thickness and subject density due to beam attenuation.