This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Opioids, Subject name: Pharmacology
An opioid which is an anti tussive action is? 
Select and explain. 
A. Dextromethorphan, B. Oxeladin, C. Codeine, D. Narcotine
C: Codeine
Answer: C: Codeine 
Explanation: ANSWER: (C) Codeine REF: KDT 5th ed p. 197ANTITUSSIVESOpioidsNon opioidsCodeinePholocodieneNoscapine or narcotineDextrpmethorphanOxeladin chlorphdianol