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': 'No. of cusps in mandibular 1st molar: \nSelect and explain. \nA. 4, B. 3, C. 5, D. 6', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]