Illustration $5$ and $6$: Including a library in your source code is required for the compiler to know function definitions. The Standard Library implementation includes in $.$ Namespace declaration is also required to tell the compiler a function belongs to its namespace. Which lines in Illustration $5$ and $6$ show this?

Group of answer choices

$5$: $2,6$: $1$

$5$: $4-6,6$: $2$

$5$: $8,6$: $3$

$5$: none, $6$: $9$

Illustration $5$:

$1.$ #include $//$ cin, cout, endl

$2.$ #include

$3.$

$4.$ using std: :cout;

$5.$ using std: :endl;

$6.$ using std: :string;

$7.$

$8.$ template

$9.$ const T& max$($const T& x$,$ const T& y$)$

$10.\{$

$11.$ if$($y $<$ x$)$

$12.$ return x;

$13.$ return y;

$14.\}$

$15.$

$16.$ int main $()$

$17.\{$

$18.$ cout $<<$ max $(3,7)<<$ endl;

$19.$ cout $<<$ max $(3\mathrm{.}0,4\mathrm{.}0)<<$ endl;

$20.$ cout $<<$ max$(3,8\mathrm{.}0)<<$ endl;

$21.$ cout $<<$ max$(\text{'}$A$\text{'},\text{'}$C$\text{'})<<$ endl;

$22.$ cout $<<$ max$("$hello$",$ "world"$)$;

$23.$ return $0$;

$24.\}$

$25.\}//$ Page $21$