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': 'The size of ovum is : \nSelect and explain. \nA. 0.133 mm, B. 0.144 mm, C. 0.2 mm, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 0.133 mm', 'role': 'assistant'}]