This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2018, Subject name: Orthopaedics
[{'content': 'A 12 year old boy presents with chronic knee pain for 2 years/. Knee x ray is shown. Probable diagnosis: \nSelect and explain. \nA. Chronic osteomyelitis, B. Osteosarcoma, C. Rickets, D. Hyperparathyroidism', 'role': 'user'}, {'content': 'Answer: C \nExplanation: * The x-ray shows lower end of femur with flaring and irregular margins but the epiphysis is normal.* There is no white line in epiphysis, hence scurvy is ruled out.* Absence of lytic lesions rules out hyperparathyroidism.* Malignancy is ruled out as there is no periosteal reaction or bone growth is seen.* Rickets shows flaring of metaphysis and widening of the growth', 'role': 'assistant'}]