This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Trauma, Subject name: Surgery
Jefferson fracture is fracture of which spine 
Select and explain. 
A. C1, B. C2, C. C3, D. C4
A: C1
Answer: A: C1 
Explanation: Jefferson fracture is disruption of C1 ring in multiple locations; blow-out of ringHangman fracture is bilateral C2 pedicles with spondylolisthesisSabiston 20e pg: 443