This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Anatomy
All are forms of opioid replacement therapies except 
Select and explain. 
A. Naloxone, B. Buprenorphine, C. LAAM, D. Methadone
A: Naloxone
Answer: A: Naloxone 
Explanation: Rest are oral opioids used for substitution