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
All these are Included In active tissue engineering, except 
Select and explain. 
A. Antigens fibroblasts, B. Bilayered cell therapy, C. Enamel matrix derivative, D. Acellular dermal matrix
D: Acellular dermal matrix
Answer: D: Acellular dermal matrix 
Explanation: None