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 effective pressure to be achieved in vacuum extraction is : \nSelect and explain. \nA. 0.1 kg/cm2, B. 0.1 kg/cm2, C. 0.6 kg/cm2, D. 1.2 kg/cm2', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 0.6 kg/cm2', 'role': 'assistant'}]