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: Radiology
[{'content': "All the following are causes of secondary achalasia except \nSelect and explain. \nA. Allgrove's Syndrome, B. Multiple endocrine neoplasia, C. Kala azar, D. Chaga's disease", 'role': 'user'}, {'content': "Answer: C \nExplanation: Causes of Secondary achalasia:\n\nTriple 'A' or Allgrove's Syndrome\nMEN\nChaga's disease\nCancer Invading LES.", 'role': 'assistant'}]