Consider the following Python program:

List all the variables, along with the program units where they are declared, that are visible in the bodies of sub1, sub2, and sub3, assuming static scoping is used.

x = 1; y = 3; %3D z = 5; def subl () : = 7; a = y = 9; z = 11; def sub2 () : global X; a = 13; x = 15; W = 17; def sub3 () : nonlocal a; a = 19; b = 21; z = 23;