MS-0100

A 56-year-old male is admitted to the hospital with increasing fatigue and difficulty exercising. After undergoing various tests, including echocardiography and right heart catheterization, it is determined that he has pulmonary arterial hypertension (PAH) with a mean pulmonary artery pressure of 35 mmhg and a pulmonary capillary wedge pressure of 8mmhg. One of the medications prescribed for him is ambrisentan. What is the mechanism of action of this drug?