Which of the following conditions is classified as an acyanotic congenital heart defect?

A ventricular septal defect is classified as an acyanotic congenital heart defect because it involves a communication between the ventricles of the heart, allowing blood to flow from the left ventricle to the right ventricle due to the higher pressure in the left ventricle. This left-to-right shunt increases blood flow to the lungs but typically does not result in significant cyanosis, as the oxygenated blood remains in the arterial system and the systemic circulation.

In contrast, conditions like transposition of the great vessels, tetralogy of Fallot, and hypoplastic left heart syndrome create significant shunting or mixing of oxygenated and deoxygenated blood, leading to inadequate oxygenation of the systemic blood and resulting in cyanosis. Thus, ventricular septal defect stands out as an acyanotic defect due to its hemodynamics that preserve adequate oxygen delivery while still being a significant heart defect that may require surgical intervention depending on its size and associated symptoms.