Consider the following JavaScript skeletal program:

// The main program

var x;

function sub1() {

var x;

function sub2() {

...

}

}

function sub3() {

...

}

Assume that the execution of this program is in the following unit order:

main calls sub1 main calls sub2 main calls sub3

a. Assuming dynamic scoping, in the following, which declaration of x is the correct one for a reference to x?

i. sub1

ii. sub2

iii. sub3

b. Repeat part a, but assume dynamic scoping