De or het winkelopenstelling?

The correct Dutch article is:

de winkelopenstelling

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

How to use winkelopenstelling

the winkelopenstellingde winkelopenstelling
this winkelopenstellingdeze winkelopenstelling
that winkelopenstellingdie winkelopenstelling
our winkelopenstellingonze winkelopenstelling
your winkelopenstellingjouw winkelopenstelling
every winkelopenstellingelke winkelopenstelling
which winkelopenstelling?welke winkelopenstelling?
a big winkelopenstelling / the big winkelopenstellingeen grote winkelopenstelling, de grote winkelopenstelling