Consider the following JavaScript program:

$//$ The main program

varx;

function sub$1()\{$

var x;

function sub$2()\{$

$...$

$\}$

$\}$

function sub$3()\{$

$\}$

Assume that the execution of this program is in the following unit order:

main calls sub$1$

sub$1$ calls sub$2$

sub$2$ calls sub$3$

Assuming static scoping, which declaration of $x$ is the correct one for a reference to $x$ in sul

sub$1$

sub$2$

sub$3$

main