A linked list of Strings named list has been declared and initialized.

Assume that the following code is run on list:

list.add$(3)$;

list.addFirst$(1)$;

list.addLast$(2)$;

list.remove$(0)$;

list.addFirst$(7)$;

list.remove$(3)$;

list.addFirst$(6)$;

list.addLast$(4)$;

list.remove$(3)$;

list.addFirst$(2)$;

list.addFirst$(3)$;

list.remove$(7)$;

list.addLast$(0)$;

list.addLast$(9)$;

What does list.indexOf$("0")$ return?

$5$

$0$

$4$

$3$