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
In normal occlusion, with which grooves / surface of the permanent mandibular first molar does the mesiobuccal cusp of the permanent maxillary first molar occlude: 
Select and explain. 
A. Distobuccal groove, B. Mesial surface, C. Mesiobuccal surface, D. Transverse groove
C: Mesiobuccal surface
Answer: C: Mesiobuccal surface 
Explanation: None