This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abnormal labor, Subject name: Anatomy
[{'content': 'The following statements are related to occipitoposterior except : \nSelect and explain. \nA. Malrotation of occiput may cause occipitoacral arrest, B. 10% cases are associated with anthropoid or android pelvis, C. Incomplete forward rotation of occiput may cause deep transverse arrest, D. Non rotation of occiput may cause', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Occipitoposterior position : In more than 50% of occipitoposterior position is associated with anthropoid or android pelvis Ref: Datta Obs 9e pg 343.', 'role': 'assistant'}]