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: Surgery
Critical Limb ischemia results from 
Select and explain. 
A. Mild Arterial Occlusive Disease, B. Moderate Arterial Occlusive disease, C. Severe Arterial occlusive disease, D. All of the above
C: Severe Arterial occlusive disease
Answer: C: Severe Arterial occlusive disease 
Explanation: None