De or het gunstregeling?

The correct Dutch article is:

de gunstregeling

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

How to use gunstregeling

the gunstregelingde gunstregeling
this gunstregelingdeze gunstregeling
that gunstregelingdie gunstregeling
our gunstregelingonze gunstregeling
your gunstregelingjouw gunstregeling
every gunstregelingelke gunstregeling
which gunstregeling?welke gunstregeling?
a big gunstregeling / the big gunstregelingeen grote gunstregeling, de grote gunstregeling