This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: X-RAYS, Subject name: Radiology
To which of the following, milliamperes-second is not related to? 
Select and explain. 
A. Quantity, B. Blackening of film, C. Contrast, D. Quality
D: Quality
Answer: D: Quality 
Explanation: mAs is directly propoional to quantity(number) of X-rays , blackening of film and contrast. Milliampere-seconds more commonly known as mAs is a measure of radiation produced (milliamperage) over a set amount of time (seconds) an x-ray tube. It directly influences the radiographic density, when all other factors are constant.