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 believed to be effective in the treatment of postoperative shivering? 
Select and explain. 
A. Ondansetron, B. Diclofenac sodium, C. Pethidine, D. Paracetamol
C: Pethidine
Answer: C: Pethidine 
Explanation: Pethidine is the most effective drug for the treatment of post-operative shivering. Other drugs that can be used for this purpose are clonidine, doxapram, ketanserin and alfentanil.