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': 'Hot air over holding time and temperature: \nSelect and explain. \nA. 121degC for 15 minutes, B. 160degC for 45 minutes, C. 135degC for 5 minutes, D. 190degC for 30 minutes', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. (d) 190degC for 30 minutes', 'role': 'assistant'}]