De or het stockoplossing?

The correct Dutch article is:

de stockoplossing

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

How to use stockoplossing

the stockoplossingde stockoplossing
this stockoplossingdeze stockoplossing
that stockoplossingdie stockoplossing
our stockoplossingonze stockoplossing
your stockoplossingjouw stockoplossing
every stockoplossingelke stockoplossing
which stockoplossing?welke stockoplossing?
a big stockoplossing / the big stockoplossingeen grote stockoplossing, de grote stockoplossing