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: Gynaecology & Obstetrics
[{'content': 'Most frequent chromosomal abnormality found in those with heart defect \nSelect and explain. \nA. Trisomy 13, B. Trisomy 21, C. Trisomy 18, D. Monosomy X', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Trisomy 21 >> Trisomy 18 >> 22q Microdeletion >> Trisomy 13 >> monosomy X.\nThis is order of occurrence of heart defect most commonly and frequently.', 'role': 'assistant'}]