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 is the shoest acting betablocker: September 2006 
Select and explain. 
A. Acebutolol, B. Sotalol, C. Bisoprolol, D. Esmolol
D: Esmolol
Answer: D: Esmolol 
Explanation: Ans. D: Esmolol