**Core Concept**
The aortic hiatus is a significant anatomical structure that allows the aorta and other vital structures to pass from the thoracic cavity to the abdominal cavity. It is located at the level of the T12 vertebra and plays a crucial role in the circulation of blood and the innervation of abdominal organs.

**Why the Correct Answer is Right**
The aortic hiatus is a natural opening in the diaphragm through which the aorta, thoracic duct, and sometimes the azygos vein pass from the thoracic cavity to the abdominal cavity. This opening is essential for the proper circulation of blood and the drainage of lymphatic fluid from the abdominal and pelvic regions. The thoracic duct, which is the main lymphatic vessel in the body, passes through the aortic hiatus to empty into the bloodstream at the junction of the left jugular and left subclavian veins.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the correct structures that pass through the aortic hiatus.
**Option B:** This option is incorrect because it mentions the inferior vena cava, which actually passes through the caval opening of the diaphragm, not the aortic hiatus.
**Option C:** This option is incorrect because it mentions the esophagus, which passes through the esophageal hiatus of the diaphragm, not the aortic hiatus.

**Clinical Pearl / High-Yield Fact**
Remember that the aortic hiatus is a critical anatomical landmark that allows vital structures to pass between the thoracic and abdominal cavities. Knowledge of this opening is essential for surgeons and anesthesiologists performing thoracic and abdominal surgeries.

**Correct Answer:** C. aorta, thoracic duct, and azygos vein.