### Core Concept
Dohlman's procedure is a type of endoscopic treatment for a specific condition affecting the upper digestive tract. It involves the use of a rigid or flexible endoscope to perform a particular intervention. The procedure is aimed at alleviating symptoms associated with a congenital or acquired anomaly of the esophagus.

### Why the Correct Answer is Right
Dohlman's procedure is specifically designed to treat Zenker's diverticulum, a condition characterized by the formation of a mucosal herniation through a weakness in the muscular wall of the pharynx, just above the cricopharyngeus muscle. The procedure involves the use of an endoscope to visualize the diverticulum and then a dilator or a stapler is used to reduce the size of the diverticulum or to obliterate it. This approach helps to alleviate symptoms such as dysphagia, regurgitation, and aspiration.

### Why Each Wrong Option is Incorrect
**Option A:** Rectal prolapse is a condition where the rectum loses its normal attachments inside the body, allowing it to protrude out through the anus. Dohlman's procedure is not used to treat rectal prolapse.

**Option B:** Esophageal achalasia is a disorder of the esophagus that makes swallowing difficult, caused by abnormal muscle contractions. Dohlman's procedure is not used to treat esophageal achalasia.

**Option C:** Cancer of the esophagus involves the abnormal growth of cells in the esophagus, which can invade surrounding tissues and spread to other parts of the body. Dohlman's procedure is not used to treat cancer of the esophagus.

### Clinical Pearl / High-Yield Fact
Dohlman's procedure is a minimally invasive approach to treating Zenker's diverticulum, which offers several benefits over traditional open surgery, including reduced recovery time and less postoperative pain.

### Correct Answer Line
✓ Correct Answer: D. Zenker's diverticulum