This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal system, Subject name: Radiology
[{'content': 'Which is the earliest radiologic feature of bone infection \nSelect and explain. \nA. Destructive lytic lesion, B. Presence of periosteal reaction, C. Soft tissue edema, D. Appearance of sequestra', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Sequence of changes in bone infection (osteomyelitis) on X-ray are : Earliest finding of osteomyelitis on X ray within 8 days is soft tisse swelling and loss of soft tissue planes Bone destruction and formation of periosteal reaction seen at 10-14 days Invoucrum formation at 3 weeks Sequestrum formation at 4 weeks', 'role': 'assistant'}]