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': 'Organism involved in smooth surface caries is\n1. Streptococcus mutans 2. Actinomyces viscosus\n3. Lactobacillus\t4. Campylobacter \nSelect and explain. \nA. only 1, B. only 2, C. 1 and 3, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]