The output of the following BST code is: $*$

insert$($root$,9)$;

insert$($root$,7)$;

insert$($root$,5)$;

insert$($root$,8)$;

insert$($root$,4)$;

insert$($root$,6)$;

postorder$($root$)$;

$465789$

$456879$

$465879$

$456789$