This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Adrenal, Subject name: Medicine
[{'content': 'Most common cause of ectopic ACTH production- \nSelect and explain. \nA. Renal cell carcinoma, B. Hepatocellular carcinoma, C. Small cell carcinoma lung, D. Pheochromacytoma', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e.. Small cell carcinoma lungo Ectopic ACTHproduction accounts for 10-20% cases of cushings syndromeo Small cell lung carcinoma (SCLC) is by far the most common causes of ectopic ACTH.# If accounts for more than 50%cases of cushings syndrome due to ectopic ACTH production.Other carcinomas associatedThymic carcinoid (15%)Islet cell tumour (10%)Bronchial carcinoid (10%)Other carcinoids (5%)Pheochromocytoma (2%)", 'role': 'assistant'}]