Why Is Protein Binding an Important Characteristic of Local Anesthetic

Why is protein binding an important characteristic of local anesthetic drugs?

A) Increased protein binding allows more cations (RNH+) to bind to the receptor sites within the sodium channels, prolonging the presence of anesthetic at the site of action.
B) Increased protein binding allows more RN molecules to bind to the receptor sites within the sodium channels, prolonging the presence of anesthetic at the site of action.
C) Decreased protein binding allows more cations (RNH+) to bind to the receptor sites within the sodium channels, prolonging the presence of anesthetic at the site of action.
D) Decreased protein binding allows more RN molecules to bind to the receptor sites within the sodium channels, prolonging the presence of anesthetic at the site of action.