**Core Concept**
Total anomalous pulmonary venous connection (TAPVC) is a rare congenital heart defect where the pulmonary veins are abnormally connected to the systemic venous system instead of the left atrium. This results in the oxygenated blood returning to the right side of the heart instead of the left, leading to decreased oxygenation of the systemic circulation.

**Why the Correct Answer is Right**
The most common type of TAPVC is Supracardiac TAPVC, where the pulmonary veins connect to the superior vena cava or its tributaries. This is due to the embryological development of the pulmonary veins, which typically connect to the left atrium. However, in Supracardiac TAPVC, the pulmonary veins develop abnormally and connect to the superior vena cava, leading to the characteristic symptoms of cyanosis and shortness of breath.

**Why Each Wrong Option is Incorrect**
**Option A:** **Infracardiac TAPVC** is a less common type of TAPVC where the pulmonary veins connect to the inferior vena cava or its tributaries, not the superior vena cava.
**Option B:** **Cardiac TAPVC** is a rare type of TAPVC where the pulmonary veins connect to the coronary sinus or the left atrial appendage, not the superior vena cava.
**Option C:** **Mixed TAPVC** is a type of TAPVC where the pulmonary veins connect to both the superior and inferior vena cava, but it is not the most common type.

**Clinical Pearl / High-Yield Fact**
Supracardiac TAPVC is often associated with a left-to-right shunt at the atrial level, leading to pulmonary hypertension and eventual cyanosis. A chest X-ray typically shows an enlarged cardiac silhouette with a "snowman" sign due to the dilated superior vena cava and right atrium.

**Correct Answer: C. Supracardiac TAPVC.**