**Core Concept**
Achalasia cardia is a motility disorder of the esophagus characterized by the failure of the lower esophageal sphincter (LES) to relax, leading to difficulty in swallowing and regurgitation of food. The treatment of achalasia cardia aims to relax the LES and improve esophageal emptying.

**Why the Correct Answer is Right**
The treatment of achalasia cardia often involves the use of nitrates or calcium channel blockers to relax the LES. However, the most effective treatment is usually **botulinum toxin injection** into the LES, which temporarily paralyzes the muscle and allows for relaxation. Another option is **pneumatic dilation**, which mechanically widens the LES to improve passage of food. Additionally, **peroral endoscopic myotomy (POEM)** is a minimally invasive surgical procedure that involves making a mucosal incision in the esophagus and cutting the muscular layer of the LES to improve relaxation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not directly address the pathophysiology of achalasia cardia.
**Option B:** This option is incorrect as it is not a commonly used treatment for achalasia cardia.
**Option C:** This option is incorrect as it is not a specific treatment for achalasia cardia.

**Clinical Pearl / High-Yield Fact**
Achalasia cardia is often associated with other motility disorders, such as diffuse esophageal spasm and esophageal diverticula. Patients with achalasia cardia may also experience weight loss, dysphagia, and regurgitation of food.

**Correct Answer:** C.