Closure of the bicuspid valve specifically occurs when:
a. the valve contracts
b. pressure inside the left ventricle is less than pressure in the pulmonary artery
c. pressure inside the right atrium is greater than pressure in the left atrium
d. pressure in the right atrium is greater than pressure in the right ventricle
e. pressure in the left ventricle is greater than pressure in the left atrium
f. pressure in the right ventricle is greater than pressure in the right atrium