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
Clasp used in distobuccal undercut of distal extension removable partial denture are all expect? 
Select and explain. 
A. Combination clasp, B. Embrassure clasp, C. Circumferential clasp, D. Reverse circlet clasp
A: Combination clasp
Answer: A: Combination clasp 
Explanation: None