**Core Concept**
The patient's symptoms of severe heartburn, history of hypertension treated with captopril, and clinical findings of Raynaud disease, multiple facial telangiectasias, and taut skin on the hands are suggestive of systemic sclerosis (scleroderma). Esophageal manometry is ordered to evaluate esophageal motility and assess for any abnormalities.

**Why the Correct Answer is Right**
The patient's symptoms of severe heartburn are likely due to esophageal dysmotility, which is a common finding in systemic sclerosis. The disease causes fibrosis and atrophy of the esophageal smooth muscle, leading to impaired peristalsis and decreased esophageal clearance. This results in gastroesophageal reflux disease (GERD) symptoms. The use of captopril, an angiotensin-converting enzyme (ACE) inhibitor, may also contribute to the development of GERD by increasing gastric acid secretion.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not take into account the patient's underlying systemic sclerosis, which is the most likely cause of her esophageal symptoms.

**Option B:** This option is incorrect because it does not consider the patient's history of hypertension and the use of captopril, which may have contributed to her development of GERD.

**Option C:** This option is incorrect because it does not reflect the typical findings in systemic sclerosis, where esophageal dysmotility is more common than achalasia.

**Option D:** This option is incorrect because it does not account for the patient's systemic sclerosis and the resulting esophageal dysmotility.

**Clinical Pearl / High-Yield Fact**
Systemic sclerosis is a multisystem disease that can affect multiple organs, including the skin, lungs, kidneys, and gastrointestinal tract. It is essential to consider the patient's overall clinical picture when evaluating symptoms and ordering diagnostic tests.

**Correct Answer: C. Esophageal dysmotility.**