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: Pharmacology
An agent added to local anaesthetics to speed the onset of action is : 
Select and explain. 
A. Methylparaben, B. Bicarbonate, C. Fentanyl, D. Adrenaline
B: Bicarbonate
Answer: B: Bicarbonate 
Explanation: None