**Core Concept**
Coarctation of the aorta is a congenital anomaly characterized by the narrowing of the aortic isthmus, typically at the junction of the aortic arch and the descending aorta. This narrowing leads to increased resistance to blood flow, resulting in hypertension and decreased blood pressure distal to the obstruction. The increased pressure in the upper body can cause erosion of the ribs, leading to the characteristic "rib notching" seen on chest radiographs.

**Why the Correct Answer is Right**
In coarctation of the aorta, the narrowing of the aortic isthmus leads to increased pressure in the upper body, causing hypertension, which is consistent with the patient's high blood pressure. The weak femoral pulse compared to the radial and carotid pulses is due to the obstruction of blood flow to the lower body, resulting in decreased perfusion of the lower extremities. The rib notching is a classic sign of coarctation of the aorta, caused by the erosion of the ribs due to the increased pressure in the upper body.

**Why Each Wrong Option is Incorrect**
**Option A:** Femoral artery thrombosis would cause a sudden loss of pulse in the affected limb, which is not consistent with the gradual onset of symptoms seen in this patient.

**Option C:** Raynaud's disease is characterized by vasospasm of the digital arteries, leading to decreased blood flow to the fingers and toes, which is not consistent with the patient's symptoms.

**Option D:** Takayasu's arteritis is a large vessel vasculitis that affects the aorta and its major branches, but it typically presents with symptoms of aortic insufficiency, such as aortic regurgitation, which is not mentioned in this patient's presentation.

**Clinical Pearl / High-Yield Fact**
Coarctation of the aorta is often associated with other congenital anomalies, such as Turner syndrome, bicuspid aortic valve, and pectorus excavatum. It is essential to suspect coarctation of the aorta in patients with hypertension, weak pulses in the lower extremities, and rib notching on chest radiographs.

**✓ Correct Answer: B. Coarctation of aorta**