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: Orthopaedics
[{'content': 'All of the following joints ossify 16 years of age except \nSelect and explain. \nA. Ankle, B. Hip, C. Knee, D. Elbow', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Milking Position, to remember age of ossification of skeletal maturity.\n\nJoints facing toward sky like shoulder, wrist and knee ossify around 18 years.\nJoints facing towards ground like hip, ankle and elbow ossify around 16 years.', 'role': 'assistant'}]