D is the correct answer.
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The illustration demonstrates the four components of the Tetralogy of Fallot (Choice D): (1) pulmonic stenosis, (2) overriding aorta, (3) ventricular septal defect (VSD), and (4) right ventricular hypertrophy. This most-common cause of cyanotic congenital heart disease varies in severity; it may present as early as birth or later in the first years of life. Aortic valve atresia (Choice A) is incorrect; the aortic valve is formed and of normal caliber in the illustration. As it does not disrupt oxygenation of blood, this condition does not usually cause cyanosis. Of note, complete aortic valve atresia is incompatible with life. Patent ductus arteriosus (PDA) (Choice B) is incorrect; no communication between the pulmonary artery and aorta is exhibited. Embryologically, it is a remnant of the ductus arteriosus necessary for fetal circulation. Clinically, this condition leads to pulmonary hypertension and right heart hypertrophy due to excess blood flowing through the pulmonary artery. Patent foramen ovale (PFO) (Choice C) is incorrect; no atrial septal defect is exhibited in the illustration. Embryologically, it is a remnant of the foramen ovale necessary for fetal circulation. Though PFO increases the risk of a paradoxical venous-to-arterial embolus, it would not affect exercise tolerance and most patients are asymptomatic. In transposition of the great vessels (Choice E), the aorta arises from the right ventricle, the pulmonary artery from the left ventricle; thus, this answer is incorrect. Unless a shunt exists to allow mixing of venous and arterial blood, this cyanotic congenital heart disease is incompatible with life. Adapted from http://commons.wikimedia.org/wiki/File:Heart_tetralogy_fallot.svg