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
There is <2 cm painful swelling responsive to salicylates, this is: 
Select and explain. 
A. Osteoma, B. Osteochondroma, C. Osteoid osteoma, D. Osteoblastoma
C: Osteoid osteoma
Answer: C: Osteoid osteoma 
Explanation: None