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: Anaesthesia
Which of the following is the mechanism of action of local anaesthetics? 
Select and explain. 
A. Block Na+ channel, B. Block K+ channel, C. Open Na+ channel, D. Block Ca+ channel
A: Block Na+ channel
Answer: A: Block Na+ channel 
Explanation: "Local anaesthetics block the conduction of action potential by blocking voltage gated Na+ channels". Ref: Medical Pharmacology at a Glance By Michael J. Neal 4/e, Page 15 ; Instant Pharmacology By Kourosh Saeb Parsy, Ravi G, Assomul, Fakkar J. Khan, Kasra Saeb Parsy, Eamonn Kelly; Page 123