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': 'Knots in umbilical cord \nSelect and explain. \nA. Caused by fetal movement, B. Very high risk of still birth, C. Dangerous in Diamniotic twins, D. Always indication for C-section', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Knots in umbilical cord are caused by fetal movements.\nCommon in monoamniotic twins (dangerous). C-section is not indicated always.', 'role': 'assistant'}]