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
VRF vertical root fracture primarily occurs in which direction? 
Select and explain. 
A. Mesiodistal, B. Faciolingual, C. Coronal and extending apically, D. No primary direction
B: Faciolingual
Answer: B: Faciolingual 
Explanation: None