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 process of attenuation can be achieved by all except 
Select and explain. 
A. Growing bacteria in adverse environment, B. Growing bacteria in unconventional host, C. Serial passage in an experimental host, D. Repeated cultures in artificial media
C: Serial passage in an experimental host
Answer: C: Serial passage in an experimental host 
Explanation: None