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
The shape of the occlusal surface of the permanent maxillary first molar is: 
Select and explain. 
A. Oval, B. Trapezoidal, C. Triangular, D. Rhomboidal
D: Rhomboidal
Answer: D: Rhomboidal 
Explanation: None