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: Surgery
Main disadvantage of dry heat used for sterilization is that: 
Select and explain. 
A. It is time consuming, B. Rusts the instruments, C. Dulls the sharp instruments, D. Ineffective sterilization
A: It is time consuming
Answer: A: It is time consuming 
Explanation: None