input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A 72-year-old Caucasian male presents to your office with dysphagia and halitosis. If this patient is also found to have cricopharyngeal muscle dysfunction, which of the following is the most likely cause of his presenting symptoms?   (A) Gastroesophageal reflux disease   (B) Esophageal candidiasis   (C) Meckel's diverticulum   (D) Zenker's diverticulum
output: ["(D) Zenker's diverticulum <> answer", 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', "(A) Gastroesophageal reflux disease  (B) Esophageal candidiasis  (C) Meckel's diverticulum  (D) Zenker's diverticulum <> possible answers", '  A 72-year-old Caucasian male presents to your office with dysphagia and halitosis. If this patient is also found to have cricopharyngeal muscle dysfunction, which of the following is the most likely cause of his presenting symptoms? <> context']