Dynamic vs Static Scoping problem?

Yes, this is a class problem. However there was no lecture on this and there are no examples in the book so I don't understand. The professor specifically instructed us to "google it". So:

Consider the following program:

proc main

int a, x, z;

proc A:

proc B;

int x, z;

{ x := 4; call C; print x; } (end B)

proc C;

int a, z; { x := 6; z := 9; a := 2; call D; print x; print a;} (end C)

{ x := 5; z := 7; call B; print x; } (end A)

proc D;

int x, b;

proc E;

int x; { x := 7 ; call F; print x; } (end E)

proc F;

proc G;

{print z; x:= 10 ; a:= 8 ;} (end G)

{print x; call G; x:=9 ; } (end F)

{ x := 8 ; call E; print x; } (end D)

{ a := 4; x:= 3; z := 11 ; call A; print x; print a;} (end main)

(a) What is the program output assuming static scoping rules are employed?

(b) What is the corresponding output when dynamic scoping rules are employed?

(c) List the units that proc G can call (assuming static scoping ).