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
Which of the following do not contribute to arch stability? 
Select and explain. 
A. Cusps, B. Root forms, C. Embrasures, D. Periodontal fibers
C: Embrasures
Answer: C: Embrasures 
Explanation: None