Showthestackwithallactivationrecordinstances,includingstaticand dynamic chains, when execution reaches position $1$ in the following skeletal program. Assume bigsub is at level $1.$

function bigsub$()\{$ var mysum; function a$()\{$

var x;

function b$($sum$)\{$

var y$,$ z; $...$

c$($z$)$;

$...$

$\}//$ end of b

$...$

b$($x$)$;

$...$

$\}//$ end of a function c$($plums$)\{$

$...<-----------------------------1\}//$ end of c

var l;

$...$

a$()$;

$...$

$\}//$ end of bigsu