All of these statements are incorrect EXCEPT: _______________

a. Right atrioventricular valve prevents the backflow of blood into the left ventricle when the ventricles relax.
b. Left atrioventricular valve prevents the backflow of blood into the left ventricle when the ventricles relax.
c. Aortic semilunar valve prevents the backflow of blood into the left ventricle when the ventricles relax
d. Pulmonary semilunar valve prevents the backflow of blood into the left ventricle when the ventricles relax