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
The optimal time and temperature required for sterilization in an autoclave is 
Select and explain. 
A. 140°C x 2 hrs. x 10 lbs pr, B. 121°F x 15 mts. x 15 lbs pr, C. 121°C x 15 sec. x 15 lbs pr, D. 121°C x 15 mts. x 15 lbs pr
D: 121°C x 15 mts. x 15 lbs pr
Answer: D: 121°C x 15 mts. x 15 lbs pr 
Explanation: None