De or het musicalafdeling?

The correct Dutch article is:

de musicalafdeling

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

How to use musicalafdeling

the musicalafdelingde musicalafdeling
this musicalafdelingdeze musicalafdeling
that musicalafdelingdie musicalafdeling
our musicalafdelingonze musicalafdeling
your musicalafdelingjouw musicalafdeling
every musicalafdelingelke musicalafdeling
which musicalafdeling?welke musicalafdeling?
a big musicalafdeling / the big musicalafdelingeen grote musicalafdeling, de grote musicalafdeling