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': 'Posterior dislocation of hip is characterized by- \nSelect and explain. \nA. Marked shoening of limb, B. Lengthening of lim, C. No change in limb length, D. Extension deformity', 'role': 'user'}, {'content': "Answer: A \nExplanation: * There is typical deformity of flexion, adduction and internal rotation with marked shoening of limb. Ref: Apley's 9th/e p.844", 'role': 'assistant'}]