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
Creation of an apical stop to prevent extrusion of matrix beyond apex is called: 
Select and explain. 
A. Resistance form, B. Retention form, C. Conenience form, D. None of the above.
A: Resistance form
Answer: A: Resistance form 
Explanation: None