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
Kiel bone is:
Xenograft
Allograft
Treated by detergent, sterilized and freeze dried.
Ox or calf bone denatured with 20% H2O2, acetone and sterilized. 
Select and explain. 
A. 1&3, B. 2&3, C. 1&4, D. 2&4
C: 1&4
Answer: C: 1&4 
Explanation: None