This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Integrated QBank, Subject name: Unknown
[{'content': 'A 2-year-old boy presented to the ER with stridor, shoness of breath and difficulty in swallowing. Patient also gave history of recurrent chest infections in the past for which the child was frequently hospitalized. Upper GI endoscopy was done and it was normal. Lab findings revealed normal studies. Chest x- ray What is the most likely diagnsosis: - \nSelect and explain. \nA. Achlasia cardia, B. Nutcracker esophagus, C. Diffuse esophageal spasm, D. Dysphagia lusoria', 'role': 'user'}, {'content': 'Answer: D \nExplanation: This is a case of Dysphagia lusoria due to aberrant right subclan aery. Chest x ray shows superior mediastinum widening. Barium study shows revealed persistent, smooth indentation of the posterior aspect of the upper thoracic esophagus at T4 level, suggesting external compression. CT shows the aberrant right subclan aery compressing the posterior wall of esophagus.', 'role': 'assistant'}]