In Humans, Atrial Septal Defect Is a Heart Defect Present

In humans, atrial septal defect is a heart defect present at birth in which blood flows between the right and left atria.This condition allows

A) blood in the ventricles to flow back into atria.
B) blood high in oxygen and blood low in oxygen to mix in the heart.
C) more efficient delivery of oxygen to tissues.
D) more blood to flow to the lungs.
E) less blood to flow to the body.