The Semilunar Valves of the Mammalian Heart

The semilunar valves of the mammalian heart

A) are the route by which blood flows from the atria to the ventricles.
B) are found only on the right side of the heart.
C) are the attachment site where the pulmonary veins empty into the heart.
D) prevent backflow of blood in the aorta and pulmonary arteries.
E) are at the places where the anterior and posterior venae cavae empty into the heart.