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: Pharmacology
Respiratory depression is seen with 
Select and explain. 
A. Tranquilizers, B. Non-barbiturates, C. Synthetic narcotics, D. Antidepressants
C: Synthetic narcotics
Answer: C: Synthetic narcotics 
Explanation: None