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
Of the following in which condition local anesthesia is ineffective? 
Select and explain. 
A. Edema, B. Localized infection, C. Hematoma, D. Anemia
B: Localized infection
Answer: B: Localized infection 
Explanation: None