De or het tariefnummer?

The correct Dutch article is:

het tariefnummer

How to use tariefnummer

the tariefnummerhet tariefnummer
this tariefnummerdit tariefnummer
that tariefnummerdat tariefnummer
our tariefnummerons tariefnummer
your tariefnummerjouw tariefnummer
every tariefnummerelk tariefnummer
which tariefnummer?welk tariefnummer?
a big tariefnummer / the big tariefnummereen groot tariefnummer, het grote tariefnummer