$4$ points$)$ Given f $($x$)=$ ln $(2$x $+1^)3/(3$x $1^)5$

$,$ Which of the following is the df

dx $?.$

$[$A$]$ df

dx $=6$

$2$x $+115$

$3$x $1$

$[$B$]$ df

dx $=3$

$2$x $+15$

$3$x $1$

$[$C$]$ df

dx $=2$

$2$x $+13$

$3$x $1$

$[$D$]$ df

dx $=3(2$x $+1)2(3$x $1)55(2$x $+1)3(3$x $1)4$

$(3$x $1)10$

$($II$)(4$ points$)$ Given f $($x$)=$ x$21$

x$2$ x $,$ which of the following statements is true?

$[$A$]$ f $($x$)$ is continuous at x $=1.$

$[$B$]$ lim

x$1$ f $($x$)$ does not exists.

$[$C$]$ lim

x$1$ f $($x$)=2$

$[$D$]$ x $=1$ is a vertical asymptote of the curve y $=$ f $($x$).$

$2$