Assuming itemstack is declared before the code below as an empty stack of strings, what does the code do$?$

itemStack.push$("$Hello$")$;

System.out.println$($itemStack$.$pop$())$;

System.out.println$($itemStack$.$pop$())$;

Prints "Hello", then "null"

Throws an exception before printing anything

Prints "Hello", then throws an exception

Prints "Hello" twice