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
A microbiologist wants to develop a vaccine for prevention of attachment of diarrhoeagenic E.coli to the specific receptors in the gastro-intestinal tract. All of the following fimbrial adhesions would be appropriate vaccine candidates except - 
Select and explain. 
A. CFA-1, B. P1-Pili, C. CS-2, D. K 88
B: P1-Pili
Answer: B: P1-Pili 
Explanation: None