6. Consider the following JavaScript skeletal program: // The main program var x; function sub1() { var x; function sub2() { Assume that the execution of this program is in the following unit order: main calls sub1 sub1 calls sub2 sub2 calls sub3 function sub3() { a. Assuming static scoping, in the following, which dec- laration of x is the correct one for a reference to x? i. subi ii. sub2 iii. sub3 b. Repeat part a, but assume dynamic scoping