This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: general microbiology, Subject name: Microbiology
The following pathogen does not satisfy 'Koch's postulates'- 
Select and explain. 
A. Bacillus anthrax, B. Mycobacterium tubercolosis, C. Clostridium tetani, D. Lepra bacilli
D: Lepra bacilli
Answer: D: Lepra bacilli 
Explanation: Mycobacterium leprae is ble but not culturable. That cannot be isolated in cell-free culture. Can be grown in the footpad of mice.It is a long and strenuos process REF:Textbook of Microbiology, Ananthanarayan, and Paniker. Page no.: 346, 364