This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition, Subject name: Medicine
[{'content': 'Keshan disease is an endemic cardiomyopathy found in deficiency of \nSelect and explain. \nA. Selenium, B. Manganese, C. Chromium, D. Copper', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (Selenium) (410-H) (449-H17th)Keshan disease - found in children and young women residing in regions of china where dietary intake of selenium is low (< 20 mg/d)* Concomitant deficiencies of iodine and selenium may worsen the clinical manifestations of cretinism.', 'role': 'assistant'}]