De or het kolharing?

The correct Dutch article is:

de kolharing

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

How to use kolharing

the kolharingde kolharing
this kolharingdeze kolharing
that kolharingdie kolharing
our kolharingonze kolharing
your kolharingjouw kolharing
every kolharingelke kolharing
which kolharing?welke kolharing?
a big kolharing / the big kolharingeen grote kolharing, de grote kolharing