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: Medicine
[{'content': 'A patient with cushingoid features presents with hemoptysis, he shows no response to dexamethasone suppression test. The most likely diagnosis is: \nSelect and explain. \nA. Adrenal hyperplasia, B. Adrenal adenoma, C. Ca lung with ectopic ACTH production, D. Pituitary microadenoma', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ca lung with ectopic ACTH production', 'role': 'assistant'}]