This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Gynaecology & Obstetrics
[{'content': 'Prolonged latent phase in nullipara is defined as one exceeding \nSelect and explain. \nA. 10 hours, B. 14 hours, C. 18 hours, D. 20 hours', 'role': 'user'}, {'content': "Answer: D \nExplanation: A prolonged latent phase was defined as one exceeding 20 hours in the nullipara and 14 hours in the multiparous women.(Ref: William's Obstetrics; 25th edition)", 'role': 'assistant'}]