This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
dihydroerigotamine differs from ergotamine in the following respect 
Select and explain. 
A. It is more potent oxytocic, B. it has antimetic propey, C. it has high oral bioavailability, D. it is more potent alpha adrenergic blocker and less potent vasoconstrictor
D: it is more potent alpha adrenergic blocker and less potent vasoconstrictor
Answer: D: it is more potent alpha adrenergic blocker and less potent vasoconstrictor 
Explanation: hydrogenation of ergot alkaloids decrease their vasoconstrictor action and increase the Alpha blocking activity Ref-KDT 6/e p168