A 45-year-old male presents with a history of crushing nonradiating chest pain. Electrocardiography and exercise stress testing reveal no evidence of cardiac edema. A more detailed history is taken, and the patient states that he has had a sensation of sticking after swallowing. He notes this sensation equally whether he is eating solids or liquids. The diagnosis that is most likely to account for these symptoms is
B. diffuse esophageal spasm
C. lower esophageal (Schatzki) ring
D. esophageal carcinoma
E. Zenker's diverticulum
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