a$.$ Evaluate $\underset{x{9}^{+}}{lim}\sqrt[\phantom{2}]{x-9}.$ b$.$ Explain why $\underset{x{9}^{-}}{lim}\sqrt[\phantom{2}]{x-9}$ does not exist. a$.\underset{x{9}^{+}}{lim}\sqrt[\phantom{2}]{x-9}=0$ b$.$ Choose the correct answer below. A$.\underset{x{9}^{-}}{lim}\sqrt[\phantom{2}]{x-9}$ does not exist because $\sqrt[\phantom{2}]{x-9}$ is defined for $x<9.$ B$.\underset{x{9}^{-}}{lim}\sqrt[\phantom{2}]{x-9}$ does not exist because $\sqrt[\phantom{2}]{x-9}$ is not defined for $x<9.$ C$.\underset{x{9}^{-}}{lim}\sqrt[\phantom{2}]{x-9}$ does not exist because $\sqrt[\phantom{2}]{x-9}$ is defined for $x>9.$ D$.\underset{?}{lim}$