A 68-year-old woman with type 2 diabetes mellitus and a 30-pound weight loss over the past two months presents to the physician with a history of nausea and bloating. Symptoms are most prominent following a meal. An outpatient gastric emptying study shows esophageal dysmotility. The best treatment option for this patient is which of the following? (A) Esophageal resection (B) Metoclopramide (C) Omeprazole (D) Ondansetron