设 $y=f \left ( \frac {2x-1}{x 1} \right )$, 且$ f'(x)= \frac {1}{3} \ln x$, 求$y'$.
$\text{A.}$ 若 $\lim \limits _{x \rightarrow 0^{ }}f(x)=0$, 则 $\lim \limits _{x \rightarrow 0^{ }}f'(x)=0$
$\text{B.}$ 若 $\lim \limits _{x \rightarrow 0^{ }}f'(x)=0$, 则 $\lim \limits _{x \rightarrow 0^{ }}f(x)=0$
$\text{C.}$ 若 $\lim \limits _{x \rightarrow \infty }f(x)= \infty $, 则 $\lim \limits _{x \rightarrow \infty }f'(x)= \infty$
$\text{D.}$ 若 $\lim \limits {x \rightarrow \infty }f'(x)=A>0$, 则 $\lim \limits {x \rightarrow \infty }f(x)= \infty$