This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
[{'content': 'The differentiating feature b/w Ectopic ACTH secretion and Cushing syndrome is - \nSelect and explain. \nA. Hypokalemic alkalosis, B. Clinical features of cushing syndrome, C. Hyperpigmentation, D. Hypeension', 'role': 'user'}, {'content': "Answer: A \nExplanation: ectopic ACTH has no typical Cushing's signs & symptoms and hypokalemic alkalosis is the predominant manifestation ( Harrison 17 pg 2255)", 'role': 'assistant'}]