This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Which of the following is investigation of choice for Zenker's diveiculum? 
Select and explain. 
A. CECT, B. Endoscopy, C. Esophageal manometry, D. Barium swallow
D: Barium swallow
Answer: D: Barium swallow 
Explanation: When suspected, the diagnosis is established by a barium swallow.. Endoscopy is usually difficult in the presence of a cricopharyngeus diveiculum and potentially dangerous, owing to the obstruction of the true esophageal lumen by the diveiculum and the associated risk of diveicular perforation. Ref: Schwaz 9/e, Page 848.