This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Microbiology (Sterilization and Bacterial Genetics), Subject name: Microbiology
For hot air oven holding time at 160degC is 
Select and explain. 
A. 2 hour, B. 15 minutes, C. 30 minutes, D. 20 minutes
A: 2 hour
Answer: A: 2 hour 
Explanation: Recommended holding time of hot air oven At 160 C is 1.5-2 hour At 170 C for 60 min At 180 C is 30 min