This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pelvis and Hip injuries, Subject name: Orthopaedics
[{'content': 'Which of the following describes grade 2 fracture neck femur? \nSelect and explain. \nA. Incomplete fracture, medial trabeculae intact, B. Complete fracture with undisplaced neck, C. Complete fracture with ischemic head, D. Moderate displacement of neck, vascularity damaged', 'role': 'user'}, {'content': 'Answer: B \nExplanation: REF : MAHESWARI 9TH ED', 'role': 'assistant'}]