De or het serviceverlening?

The correct Dutch article is:

de serviceverlening

Rule Words ending in -ing: almost always de. See the rule

How to use serviceverlening

the serviceverleningde serviceverlening
this serviceverleningdeze serviceverlening
that serviceverleningdie serviceverlening
our serviceverleningonze serviceverlening
your serviceverleningjouw serviceverlening
every serviceverleningelke serviceverlening
which serviceverlening?welke serviceverlening?
a big serviceverlening / the big serviceverleningeen grote serviceverlening, de grote serviceverlening