**Core Concept**
Tetralogy of Fallot (TOF) is a congenital heart defect characterized by four key anatomical abnormalities that lead to cyanosis and decreased oxygenation of the blood. The underlying pathophysiology involves right ventricular outflow tract obstruction, resulting in increased right ventricular pressure and volume, which in turn causes right-to-left shunting of blood through the ventricular septal defect.

**Why the Correct Answer is Right**
The four components of TOF are:
- Ventricular septal defect (VSD): a defect in the interventricular septum allowing blood to flow between the right and left ventricles.
- Pulmonary stenosis: narrowing of the right ventricular outflow tract, which obstructs blood flow to the lungs.
- Right ventricular hypertrophy: thickening of the right ventricular wall as a result of increased pressure and workload.
- Overriding aorta: the aorta is positioned over the VSD, allowing blood to flow from both the left and right ventricles into the aorta.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not a component of Tetralogy of Fallot.
* **Option B:** This option is not a component of Tetralogy of Fallot.
* **Option D:** This option is not a component of Tetralogy of Fallot.

**Clinical Pearl / High-Yield Fact**
A key clinical feature of TOF is the presence of a harsh, systolic ejection murmur due to the pulmonary stenosis, which can be associated with a palpable thrill. This murmur is often described as a "diamond-shaped" murmur due to its characteristic timing.

**Correct Answer: A, B, C**