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
[{'content': 'CHX is not effective against: \nSelect and explain. \nA. Ent.faecalis., B. Streptococcus mitis., C. Candida Albicans, D. None.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: CHX has been shown to be effective against both Ent.faecalis and Candida albicans in vitro studies.', 'role': 'assistant'}]