The Foramen Ovale Closes at Birth Due to

The foramen ovale closes at birth due to

A) higher pressure in the left atrium,which causes interatrial septum flaps to close.
B) rapid myocardial tissue growth stimulated by pregnancy hormones.
C) a rise in fetal oxygen levels,which triggers growth of the epithelial lining.
D) an increase in endothelial mucous production,which forms a plug.
E) migration of connective tissue from the right atrioventricular valve.