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: Medicine
The endotoxin of the following gram-negative bacteria does not play any part in the pathogenesis of the natural disease - 
Select and explain. 
A. Escherichia coli, B. Klebseilla spp., C. Vibrio cholerae, D. Pseudomonas aeruginosa
C: Vibrio cholerae
Answer: C: Vibrio cholerae 
Explanation: None