**Core Concept**
Double aortic arch is an embryological anomaly resulting from the persistence of the distal part of the right dorsal aortic root, which normally regresses during embryonic development. This leads to the formation of a complete or incomplete vascular ring around the trachea and esophagus.

**Why the Correct Answer is Right**
During embryonic development, the aortic arches undergo a series of complex transformations to form the adult aortic arch. In the case of double aortic arch, the right dorsal aortic root fails to regress, resulting in the formation of a second aortic arch that encircles the trachea and esophagus. This can lead to respiratory and gastrointestinal symptoms due to compression of these structures. The persistence of the right dorsal aortic root is thought to be related to genetic or environmental factors that disrupt normal embryonic development.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the embryological development of the aortic arches.
**Option B:** Hypoplastic left heart syndrome is a different congenital heart defect that affects the left side of the heart, not the aortic arches.
**Option C:** Tetralogy of Fallot is a cyanotic congenital heart defect that affects the right ventricular outflow tract, not the aortic arches.

**Clinical Pearl / High-Yield Fact**
Double aortic arch is a rare congenital anomaly that can be diagnosed prenatally or postnatally with imaging studies such as ultrasound or MRI. It requires prompt surgical intervention to relieve compression of the trachea and esophagus and prevent long-term complications.

**Correct Answer: D**