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
MC commensal gut flora in adult - 
Select and explain. 
A. Lactobacillus, B. Bacteroides, C. E. coli, D. Klebsiella
B: Bacteroides
Answer: B: Bacteroides 
Explanation: In the human intestines, Anaerobes out number aerobic bacteria a thousand fold
Among anaerobes Bacteroides are in predominant number in human gut flora.