This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Regional Anesthesia, Subject name: Anaesthesia
A 48 yrs old male with triple vessel disease and longstanding diabetes had gangrene developed in left lower foot. Which is best mode of anesthetics:- 
Select and explain. 
A. Popliteal block, B. Sciatic block, C. Femoral block, D. Saphenous nerve block
A: Popliteal block
Answer: A: Popliteal block 
Explanation: Popliteal nerve block provide excellent coverage for foot and ankle surgery, while sparing much of the hamstring muscles. The popliteal nerve block is a form of regional anesthesia utilized for a variety of foot and ankle conditions. This form of anesthesia has become a popular technique to decrease postoperative pain, decrease narcotic use, and increase patient satisfaction. There are several approaches to administering a popliteal sciatic nerve block, all with unique advantages and disadvantages. Commonly, a posterior approach is employed with the patient positioned prone. Alternatively, the lateral approach can be used with patient in the supine position. There are several approaches to administering a popliteal sciatic nerve block, all with unique advantages and disadvantages. Commonly, a posterior approach is employed with the patient positioned prone. Alternatively, the lateral approach can be used with patient in the supine position.