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 common cause of Aboion : \nSelect and explain. \nA. Ovofetal factor, B. Maternal hypoxia, C. Uterine fibroid, D. Cervical incompetence', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ovofetal factor', 'role': 'assistant'}]