$4.$ You are given $\backslash (\backslash$mathrm$\{$C$\}++\backslash )$ code as follows:

char str$[]=$"Grade";

char $*$ptr$\_$ch;

ptr$\_$ch$=\backslash$&str$[0]$;

ptr$\_$ch $=$ ptr$\_$ch$+2$;

printf$("\backslash \%$p$",$ptr$\_$ch$)$;

What is the output of the above piece of code?

$\backslash$&str$[0]$

$\backslash$&str$[4]$

$\text{'}$a$\text{'}$

None of the above