**Core Concept**
The esophagus is a muscular tube that connects the pharynx to the stomach, facilitating the passage of food through a process known as peristalsis. The extent of the esophagus is defined by its anatomical boundaries, which vary slightly between individuals.

**Why the Correct Answer is Right**
The esophagus extends from the level of the cricopharyngeal muscle (the upper border of the cricoid cartilage) to the gastroesophageal junction, where it connects with the stomach. This approximately 25-cm-long tube is divided into three main parts: the cervical esophagus, the thoracic esophagus, and the abdominal esophagus. The cervical esophagus passes through the neck and enters the thoracic cavity, where it continues as the thoracic esophagus. The abdominal esophagus then traverses the diaphragm to reach the stomach.

**Why Each Wrong Option is Incorrect**
**Option A:** This choice is incorrect because it does not accurately describe the upper border of the esophagus.
**Option B:** This option is incorrect as it does not specify the lower border of the esophagus.
**Option C:** This choice is incorrect because it does not accurately describe the middle part of the esophagus.

**Clinical Pearl / High-Yield Fact**
The extent of the esophagus is crucial for understanding various esophageal disorders, such as esophageal cancer, which often arises in the lower part of the thoracic esophagus. A thorough knowledge of esophageal anatomy is essential for accurate diagnosis and treatment.

**Correct Answer: C. Cervical to abdominal esophagus.**