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
Generally, contact areas between posterior teeth are located in which directions from the center of the proximal surface? 
Select and explain. 
A. Facially and occlusally, B. Facially and gingivally, C. Lingually and gingivally, D. Lingually and occlusally
A: Facially and occlusally
Answer: A: Facially and occlusally 
Explanation: None