De or het tariefdifferentiatie?

The correct Dutch article is:

de tariefdifferentiatie

Rule Words ending in -tie and -sie: almost always de. See the rule

How to use tariefdifferentiatie

the tariefdifferentiatiede tariefdifferentiatie
this tariefdifferentiatiedeze tariefdifferentiatie
that tariefdifferentiatiedie tariefdifferentiatie
our tariefdifferentiatieonze tariefdifferentiatie
your tariefdifferentiatiejouw tariefdifferentiatie
every tariefdifferentiatieelke tariefdifferentiatie
which tariefdifferentiatie?welke tariefdifferentiatie?
a big tariefdifferentiatie / the big tariefdifferentiatieeen grote tariefdifferentiatie, de grote tariefdifferentiatie