6. For the following JavaScript skeletal program, assume main calls fun1, fun1 calls fun3 (in line 2) and fun3 calls fun2; //the main program var v,

6. For the following JavaScript skeletal program, assume main calls fun1, fun1 calls fun3 (in line 2) and fun3 calls fun2; 

//the main program 

var v, y; 

function fun1(){ 

var x, z; 

function fun2(){ 

var z; 

... //Line 1 

} 

... //Line 2 

} 

function fun3(){ 

var y; 

... //Line 3 

} 

a. List all variables, along with the functions in which they are declared, that are visible at Line 1 in the program. 

b. Repeat part (a), but list the variables that are visible at Line 3.