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
Which of the following drugs are belived to be effective in the treatment of post-operative shivering! 
Select and explain. 
A. Ondansetron, B. Diclofenac, C. Pethidine, D. Paracetamol
C: Pethidine
Answer: C: Pethidine 
Explanation: Ans. is 'c' i.e., Pethidine o Pethidine is most effective drug for treatment of PAS (Post-anaesthesia shivering). o Other drugs used are --clonidine, doxapram, ketanserin, alfentonil, butorphanol, chlorpromazine.