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 too dark and fogged could be because of: \nSelect and explain. \nA. Increased exposure time, B. Thin patient tissues, C. Poor film storage, D. High developer concentration', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]