This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli), Subject name: Microbiology
Primarily human pathogenic bacteria is/are 
Select and explain. 
A. Salmonella typhi, B. S. paratyphi A, C. S. paratyphi B, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: S. typhi & S. paratyphi A, B and C : Man is the only natural host. Transmission ingestion of food/ water contaminated by the feces of either a carrier or a case of enteric fever. Animal commensals: S. typhimurium S. enteritidis S. newpo S. dublin S.choleraesuis