**Core Concept**
Tetralogy of Fallot (TOF) is a cyanotic congenital heart defect characterized by four components: ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy, and an overriding aorta. TOF often presents with cyanosis due to right-to-left shunting of blood.

**Why the Correct Answer is Right**
The commonest cyanotic heart disease manifesting as congestive cardiac failure during the first week of life is Tetralogy of Fallot. This occurs because of severe right ventricular hypertrophy leading to right ventricular failure, resulting in pulmonary edema and congestive cardiac failure. The obstruction to pulmonary blood flow in TOF is due to the combination of pulmonary stenosis and right ventricular hypertrophy, which causes the right ventricle to work against increased resistance, leading to failure.

**Why Each Wrong Option is Incorrect**
* **Option A:** Tricuspid Atresia is another cyanotic heart disease but it typically presents later in infancy or childhood, not in the first week of life.
* **Option B:** Ebstein's Anomaly is a congenital heart defect with an abnormal tricuspid valve, but it usually presents with signs of heart failure later in infancy or childhood.
* **Option C:** Hypoplastic Left Heart Syndrome (HLHS) is a cyanotic heart disease that usually presents with signs of heart failure in the first few days of life, but it is not the most common cyanotic heart disease.

**Clinical Pearl / High-Yield Fact**
Tetralogy of Fallot is the most common cyanotic heart disease that presents with congestive cardiac failure in the first week of life, and it is often associated with a harsh, pansystolic murmur due to the ventricular septal defect.

**Correct Answer: C. Tricuspid Atresia is incorrect, the correct answer is actually D. Tetralogy of Fallot.