De or het autoveiling?

The correct Dutch article is:

de autoveiling

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

How to use autoveiling

the autoveilingde autoveiling
this autoveilingdeze autoveiling
that autoveilingdie autoveiling
our autoveilingonze autoveiling
your autoveilingjouw autoveiling
every autoveilingelke autoveiling
which autoveiling?welke autoveiling?
a big autoveiling / the big autoveilingeen grote autoveiling, de grote autoveiling