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': 'Which is the most common cytogenetic abnormality in adult Myelodysplastic syndrome (MDS) ? \nSelect and explain. \nA. Trisomy 8, B. 20q, C. 5q, D. Monosomy 7', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]