De or het verdedigingsstelling?

The correct Dutch article is:

de verdedigingsstelling

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

How to use verdedigingsstelling

the verdedigingsstellingde verdedigingsstelling
this verdedigingsstellingdeze verdedigingsstelling
that verdedigingsstellingdie verdedigingsstelling
our verdedigingsstellingonze verdedigingsstelling
your verdedigingsstellingjouw verdedigingsstelling
every verdedigingsstellingelke verdedigingsstelling
which verdedigingsstelling?welke verdedigingsstelling?
a big verdedigingsstelling / the big verdedigingsstellingeen grote verdedigingsstelling, de grote verdedigingsstelling