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
[{'content': 'A radiographic film becomes too dark and fogged, due to: \nSelect and explain. \nA. Inappropriate processing, B. Concentrated developer, C. Poor film storage, D. Longer exposure duration', 'role': 'user'}, {'content': "Answer: C \nExplanation: FILM FOG\n\nImproper safelighting (improper filter; excessive bulb wattage; inadequate distance between safelight and work surface; prolonged exposure to safelight)\nLight leaks (cracked safelight filter; light from doors, vents, or other sources)\nOverdevelopment\xa0\nContaminated solutions\nDeteriorated film (stored at high temperature; stored at high humidity; exposed to radiation; outdated)\n\nWhite and Pharoah's Oral\xa0 Radiology Principles and Interpretation 8th edition", 'role': 'assistant'}]