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
Hot air over holding time and temperature: 
Select and explain. 
A. 121degC for 15 minutes, B. 160degC for 45 minutes, C. 135degC for 5 minutes, D. 190degC for 30 minutes
D: 190degC for 30 minutes
Answer: D: 190degC for 30 minutes 
Explanation: Ans. (d) 190degC for 30 minutes