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
All of the following causes increase in heart rate except: 
Select and explain. 
A. Halothane, B. Isoflurane, C. Sevoflurane, D. Desflurane
A: Halothane
Answer: A: Halothane 
Explanation: None