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: Unknown
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: FDA has approved the use of Bosentan for Raynaud’s phenomena