This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'Which of the following factor influence the progress of labor? \nSelect and explain. \nA. Parity, B. BMI, C. Fetal position, D. All the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Factors effecting the progress of labour : Parity of female CPD BMI Gestational age Fetal sex Twin pregnancy Ref: Fernando Arias 4e pg 338.', 'role': 'assistant'}]