This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
Tolazine is used as: 
Select and explain. 
A. A thrombin inhibitor in perpheral angiography, B. A vasodilatol' in treating coronary aery stenosis during angio procedures, C. A vasoconstrictor in treatment of varices, D. antispasmodic during biliary spasm
B: A vasodilatol' in treating coronary aery stenosis during angio procedures
Answer: B: A vasodilatol' in treating coronary aery stenosis during angio procedures 
Explanation: Ref; GOODMAN& GILMAN'S The Pharmacological Basis of the Therapeutics 10th edition (page no; 245) Tolazoline is an alpha adrenergic antagonist. used as an aid in visualizing distal peripheral vessels during aeriography and a vasodilator in treating coronary aery stenosis during angio-procedures