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': 'In normal occlusion, with which grooves / surface of the permanent mandibular first molar does the mesiobuccal cusp of the permanent maxillary first molar occlude: \nSelect and explain. \nA. Distobuccal groove, B. Mesial surface, C. Mesiobuccal surface, D. Transverse groove', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]