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
The selective β1 receptor agonist is 
Select and explain. 
A. Dobutamine, B. Dopamine, C. Atenolol, D. Salbutamol
A: Dobutamine
Answer: A: Dobutamine 
Explanation: None