Show the stack with all activation record instances, including static and dynamic chains, when execution reaches position 1 in the following skeletal program. Assume bigsub is at level 1.

The calling sequence for this program for execution to reach d is

bigsub     calls     a

a calls      b

b calls      a

a calls      c

c calls      d

function bigsub () { function a (flag) { function b () { ... a (false); } // end of b if (flag) b(); else c(); } // end of a function c() { function d() { ---1 } // end of d ... d() ; } // end of c ... a (true); } // end of bigsub