This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluid and electrolytes, Subject name: Medicine
[{'content': "'Syndrome of apparent mineralocoicoid excess' is due to deficiency of \nSelect and explain. \nA. 11a--hydroxysteroid dehydrogenase, B. 11b--hydroxysteroid dehydrogenase, C. 12a--hydroxysteroid dehydrogenase, D. 12b--hydroxysteroid dehydrogenase", 'role': 'user'}, {'content': "Answer: B \nExplanation: Syndrome of apparent mineralocoicoid excess is due to genetic deficiency of 11b-dehydrogenase-2, cause hypokalemia. Liddle's syndrome is caused by autosomal dominant gain-in-function mutations of ENaC subunits, cause hypokalemia. Loss of the transpo functions of the thick ascending loop of Henle and distal convoluted tubule nephron segments causes hereditary hypokalemic alkalosis, Bater's syndrome (BS) and Gitelman's syndrome (GS), respectively. Ref: Harrison 19e pg: 305", 'role': 'assistant'}]