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
A radiographic film becomes too dark and fogged, due to: 
Select and explain. 
A. Inappropriate processing, B. Concentrated developer, C. Poor film storage, D. Longer exposure duration
C: Poor film storage
Answer: C: Poor film storage 
Explanation: FILM FOG

Improper safelighting (improper filter; excessive bulb wattage; inadequate distance between safelight and work surface; prolonged exposure to safelight)
Light leaks (cracked safelight filter; light from doors, vents, or other sources)
Overdevelopment 
Contaminated solutions
Deteriorated film (stored at high temperature; stored at high humidity; exposed to radiation; outdated)

White and Pharoah's Oral  Radiology Principles and Interpretation 8th edition