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. 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 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