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
Wet pillow syndrome is caused by 
Select and explain. 
A. Risperidone, B. Haloperidol, C. Aripiprazole, D. Clozapine
D: Clozapine
Answer: D: Clozapine 
Explanation: Clozapine carries the side effect of sialorrhoea, termed as "Wet pillow syndrome".