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: Physiology
Location of a-1 sympathetic receptors? 
Select and explain. 
A. Blood vessels, B. Bronchi, C. Sweat glands, D. Hea
A: Blood vessels
Answer: A: Blood vessels 
Explanation: Ans. is'a' i.e., Blood vessels(Ref: Ganong 25thie p. 260)