6. Consider the following JavaScript skeletal program // The main program var X function subl(O var X function sub2(O function sub3 () Assume that the execution of this program is in the following unit order: main calls subl subl calls sub2 sub2 calls sub3 a. Assuming static scoping, in the following, which declaration of x is the correct one for a reference to x ? i. subl ii. sub2 III. sub3 b. Repeat part a, but assume dynamic scoping