## **Core Concept**
Schatzki's ring is a type of esophageal ring that is associated with dysphagia. It is a narrow, membranous ring of tissue that can cause obstruction of the esophagus. Schatzki's rings are typically found at the junction of the esophagus and the stomach.

## **Why the Correct Answer is Right**
The correct answer can be deduced by knowing the characteristics of Schatzki's ring. Schatzki's ring is known to cause dysphagia (difficulty swallowing) due to its obstructive nature. It is specifically located at the lower esophagus, near the gastroesophageal junction. The key features of Schatzki's ring include its composition and location.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Has skeletal muscle - This is incorrect because Schatzki's ring is composed of mucosal and submucosal layers, not skeletal muscle. The esophagus has a transition from skeletal to smooth muscle, but Schatzki's ring itself does not contain skeletal muscle.
- **Option C:** Contains all the layers of the esophagus - This is incorrect because Schatzki's ring is primarily made up of mucosa and submucosa, lacking the muscularis propria.
- **Option A, C are incorrect;** focusing on **a, c** being wrong helps eliminate choices.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that Schatzki's rings are associated with iron deficiency anemia (due to chronic blood loss) and can cause intermittent dysphagia, particularly to solids. They are a common cause of dysphagia and can often be treated with dilation.

## **Correct Answer:** B. b, d) Causes dysphagia, Located at lower esophagus.