This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunomodulators, Subject name: Pharmacology
Bosentan is 
Select and explain. 
A. Endothelin receptor blocker, B. ACEI, C. IIb/IIIa receptor blocker, D. None of the above
A: Endothelin receptor blocker
Answer: A: Endothelin receptor blocker 
Explanation: It is a dual endothelial receptor antagonist. FDA has approved the use of Bosentan for Raynaud's phenomenan, pulmonary aery hypeension. Ref: HL Sharma 3rd ed,Vasoactive peptides