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': 'Forceps should not be used in : \nSelect and explain. \nA. Twin delivery, B. Hydrocephalus, C. Postmaturity, D. After coming head of breech', 'role': 'user'}, {'content': 'Answer: B \nExplanation: One of the criteria before applying forceps - There should be no major cephalopelvic dispropoion by clinical pelvimetry Hydrocephalus is a most common cause of CPD. Ref: Dutta Obs 9e pg 533.', 'role': 'assistant'}]