**Core Concept**
Barrett's esophagus is a precancerous condition of the esophagus, characterized by **metaplastic** change of the esophageal mucosa, often due to chronic **gastroesophageal reflux disease (GERD)**. This condition increases the risk of developing **esophageal adenocarcinoma**.

**Why the Correct Answer is Right**
The correct answer is related to the complications that can arise from Barrett's esophagus. One of the direct complications of chronic GERD, which is also a cause of Barrett's esophagus, is the development of **esophageal strictures** due to chronic inflammation and scarring.

**Why Each Wrong Option is Incorrect**
**Option B:** Reflux esophagitis is a condition that can lead to Barrett's esophagus, rather than being a result of it.
**Option C:** Peptic ulcer is more commonly associated with the stomach or duodenum and is not a direct complication of Barrett's esophagus.
**Option D:** Achalasia is a motility disorder of the esophagus and is not directly related to Barrett's esophagus.

**Clinical Pearl / High-Yield Fact**
It's crucial to recognize that Barrett's esophagus significantly increases the risk of **esophageal adenocarcinoma**, making regular surveillance essential for patients with this condition.

**Correct Answer:** A. Stricture