3. Show the stack with all activation record instances, including static and dynamic chains, when execution reaches position 1 in the following skele tal program. Assume Bigsub is at level 1. procedure Bigsub is procedure A(Flag : Boolean) is procedure B is -- A(false); end; - of B begin - of A if flag then B; else C; end; - of A procedure C is procedure D is 1 end; - of D D; end; begin - of c -- of Bigsub 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