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
An adult patient with leg pain and gangrene of toe. His ankle to brachial aerial pressure ratio would be less than? 
Select and explain. 
A. 1, B. 0.3, C. 0.5, D. 0.8
B: 0.3
Answer: B: 0.3 
Explanation: 0.3 REF: Sabiston 18th ed chapter 66 ABI Symptoms >1 Normal 0.5-0.9 Intermittent claudication 0.3-0.5 Rest pain <0.3 Gangrene