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': 'Engagement of fetal head is : \nSelect and explain. \nA. When the occiput has gone below the pelvic in let, B. When the widest diameter of the presenting pa has passed through the pelvic inlet, C. When the presenting pa can be push into the pelvic cavity, D. Synonymous with fixation of head', 'role': 'user'}, {'content': 'Answer: B \nExplanation: When the widest diameter of the presenting pa has passed through the pelvic inlet', 'role': 'assistant'}]