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: Dental
Effect of chlorhexidine on long terms use can 
Select and explain. 
A. Suppress gram +ve and gram -ve organisms, B. Suppress all microbial flora, C. Does not cause tongue discoloration, D. Has systemic effects
B: Suppress all microbial flora
Answer: B: Suppress all microbial flora 
Explanation: None