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': 'In which of the following age group myelodysplastic syndromes (MDS) are most common? \nSelect and explain. \nA. 10-Feb, B. 15-20, C. 25-40, D. >50', 'role': 'user'}, {'content': "Answer: D \nExplanation: Idiopathic MDS is a disease of the elderly; the mean age of onset is 68 years. There is a slight male preponderance. MDS is rare in children, but monocytc leukemia can be seen. Therapy- related MDS is not age-related and may occur in as many as 15% of patients within a decade following intensive combined modality treatment for cancer. So the single best answer of choice is '>50'. Ref: Harrison's Principles of Internal Medicine, 16th Edition, Pages 624-25; R Alagappan Manual of Practical Medicine, 3rd Edition, Page 352-53.", 'role': 'assistant'}]