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: Radiology
Hallmark feature of osteomyelitis is: 
Select and explain. 
A. Identification of sequestrum, B. Pain, C. Swelling, D. None of the above
A: Identification of sequestrum
Answer: A: Identification of sequestrum 
Explanation: The hallmark of osteomyelitis is the development of sequestra. A sequestrum is a segment of bone that has become necrotic because of ischemic injury caused by the inflammatory process.
Reference: White and Pharoah's Oral Radiology Principles and Interpretation 7th edition page no 320