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
[{'content': 'Investigation of choice for parotid fistula \nSelect and explain. \nA. CT Scan, B. X-ray, C. Starch iodine Test, D. Sialogram', 'role': 'user'}, {'content': "Answer: D \nExplanation: Starch iodine Test is used for Frey's Syndrome.", 'role': 'assistant'}]