**Core Concept**
Total anomalous pulmonary venous connection (TAPVC) is a congenital heart defect characterized by the abnormal connection of pulmonary veins to the systemic venous system rather than the left atrium. This condition leads to a significant mixing of oxygenated and deoxygenated blood, resulting in cyanosis and other associated complications.

**Why the Correct Answer is Right**
The most common type of TAPVC is supracardiac, accounting for approximately 50% of all cases. In this type, the pulmonary veins connect to the superior vena cava, either directly or indirectly through a common chamber, via a vertical vein, or a duct. This anomaly occurs due to an abnormal migration of the pulmonary veins during embryogenesis, resulting in their connection to the systemic venous system rather than the left atrium.

**Why Each Wrong Option is Incorrect**
**Option A:** Infracardiac TAPVC is less common and involves the connection of pulmonary veins to the inferior vena cava. While it is a type of TAPVC, it is not the most common form.
**Option B:** Cardiac TAPVC is a rare type of TAPVC where the pulmonary veins connect to the coronary sinus or directly to the right atrium. Its rarity makes it an unlikely choice for the most common type.
**Option C:** Mixed TAPVC is a less common type where the pulmonary veins connect to both the systemic and pulmonary venous systems.

**Clinical Pearl / High-Yield Fact**
TAPVC can be categorized into five types based on the location of the anomalous connection: supracardiac, cardiac, infracardiac, mixed, and partial. Identifying the correct type is crucial for determining the appropriate surgical approach and prognosis.

**Correct Answer:** C. Cardiac TAPVC is a rare type of TAPVC where the pulmonary veins connect to the coronary sinus or directly to the right atrium.