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: Microbiology
[{'content': 'Specific reason to disallow the sample for culture- \nSelect and explain. \nA. Sample brought within 2 hr of collection, B. Sample brought in sterile plastic container, C. Sample brought in formalin, D. Sample obtained after cleaning the collection site', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]