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 ideal occlusion, facial cusps of maxillary posterior teeth oppose 
Select and explain. 
A. Grooves and embrasures, B. Grooves only, C. Marginal ridges and embrasures, D. Marginal ridges only
A: Grooves and embrasures
Answer: A: Grooves and embrasures 
Explanation: None