Questions & Answers of Runtime environments

Question No. 36

Consider the program given below, in a block-structured pseudo-language with lexical scoping and nesting of procedures permitted.

Program main;
     Var ...
     Procedure A1;
          Var ...
          Call A2;
     End A1
     Procedure A2;
          Var ...
          Procedure A21;
                Var ...
                Call A1;
          End A21
          Call A21;
    End A2
    Call A1;
End main.

Consider the calling chain: Main A1 A2 A21 A1

The correct set of activation records along with their access links is given by