**Core Concept**
The clinical scenario describes a 1-month-old infant presenting with failure to thrive and signs of congestive heart failure, along with feeble femoral pulses compared to brachial pulses. This presentation points towards a congenital heart defect, specifically one that involves obstruction of blood flow from the left ventricle to the aorta.

**Why the Correct Answer is Right**
The feeble femoral pulses compared to brachial pulses are indicative of coarctation of the aorta, a narrowing of the aortic isthmus. This narrowing restricts blood flow to the lower body, leading to decreased femoral pulses. The signs of congestive heart failure, such as failure to thrive, are secondary to the increased workload on the left ventricle due to the obstruction. Coarctation of the aorta is a type of left-sided obstructive heart disease that can be diagnosed prenatally or postnatally through echocardiography and other imaging modalities.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided, but if it were a plausible diagnosis, we would need to evaluate it based on the clinical scenario. However, given that the correct answer is not provided, we will assume that **Option A** is not the correct diagnosis for this patient.

**Clinical Pearl / High-Yield Fact**
In infants and children, coarctation of the aorta often presents with hypertension in the arms and decreased or delayed pulses in the lower extremities due to the obstruction of blood flow. This condition is often associated with Turner syndrome, Noonan syndrome, and other genetic syndromes.

**Correct Answer:** C. Coarctation of the aorta.