Determine the following limits$,$ using $$ or $-$ when appropriate, or state that they do not exist.

a$.\underset{x{9}^{}}{lim}\frac{6}{x-9}$

b$.\underset{x{9}^{-}}{lim}\frac{6}{x-9}$

c$.\underset{x9}{lim}\frac{6}{x-9}$

a$.$ Select the correct choice below and, if necessary, fill in the answer box to complete your choice.

A$.\underset{x{9}^{}}{lim}\frac{6}{x-9}=($Simplify your answer.$)$

B$.$ The limit does not exist and is neither $$ nor $-.$