This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Larynx, Subject name: ENT
Materials used for injection thyroplasty are 
Select and explain. 
A. Collagen, B. Acellular micronized human dermis, C. Gelatin powder, D. All the above
D: All the above
Answer: D: All the above 
Explanation: Injection of vocal cord with Teflon paste or gelfoam to augment and medialize the paralyzed cord so that the opposite healthy cord can easily approximate Ref: PL Dhingra Textbook of Ear, Nose and Throat, Edition 6, page - 301