A medical student working in the emergency department sees a female baby, born 2 weeks ago, who is brought in by her anxious mother. The mother tells the student that her baby seems “purple,” especially her fingers and toes, and looks extremely blue when crying. On physical examination the sleeping baby has mild cyanosis of the face and trunk, but moderate cyanosis of the extremities. Which of the following is the most common cause of cyanosis within the first few weeks of life?
(A) Atrial septal defect
(B) Patent ductus arteriosus
(C) Tetralogy of Fallot
(D) Transposition of the great vessels
(E) Ventricular septal defect