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: Pathology
[{'content': 'Lactobacilli are numerous in carious lesions because they\na They are the main causative agent\nb can produce insoluble extracellular polysaccharides\nc can attach to smooth enamel surfaces\nd are more violently cariogenic for animals than Streptococcus mutans\ne are secondary invaders \nSelect and explain. \nA. abcd are false e is true, B. abc are false d e are true, C. ab are false c d e are true, D. a is false bcde are true', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]