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
It is true regarding the normal microbial flora present on the skin and mucous membranes that - 
Select and explain. 
A. It cannot be eradicated by antimicrobial agents, B. It is absent in the stomach due to the acidic pH., C. It establishes in the body only after the neonatal period., D. The flora in the small bronchi is similar to that of the trachea
A: It cannot be eradicated by antimicrobial agents
Answer: A: It cannot be eradicated by antimicrobial agents 
Explanation: Resident Normal flora: Consists of relatively fixed types of microorganisms regularly found in a given area at a given age; if disturbed, it promptly reestablishes itself and cannot be removed permanently.