Which congenital heart lesion is characterized by a right-to-left shunt and can lead to cyanosis?

The correct choice is characterized by a right-to-left shunt, which occurs when deoxygenated blood flows from the right side of the heart to the left side, ultimately being pumped into systemic circulation. This results in reduced oxygen content in the blood and can lead to cyanosis, where the skin and mucous membranes take on a bluish color due to lack of sufficient oxygen.

Truncus arteriosus is a congenital heart defect in which a single large vessel arises from the heart, instead of having separate pulmonary artery and aorta. This condition can lead to mixing of oxygenated and deoxygenated blood, creating a right-to-left shunt option and often causing cyanosis as a result of inadequate oxygenation of systemic blood.

In contrast, conditions like an atrial septal defect create left-to-right shunting rather than right-to-left shunting, which generally does not lead to cyanosis. Mitral valve prolapse and aortic stenosis are also conditions that do not typically produce a right-to-left shunt or cyanosis.