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: Unknown
[{'content': 'Cause of recurrent missed abortion at 10 weeks - \nSelect and explain. \nA. Chromosomal abnormality, B. Cervical incompetence, C. Corpus luteum failure, D. Retroverted uterus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans-A', 'role': 'assistant'}]