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: Surgery
Which is a non absorbable suture ? 
Select and explain. 
A. Polypropylene, B. Polyglycolic acid, C. Collagen, D. All
A: Polypropylene
Answer: A: Polypropylene 
Explanation: Ans. is 'a' i.e., Polypropylene