De or het samenrotting?

The correct Dutch article is:

de samenrotting

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

How to use samenrotting

the samenrottingde samenrotting
this samenrottingdeze samenrotting
that samenrottingdie samenrotting
our samenrottingonze samenrotting
your samenrottingjouw samenrotting
every samenrottingelke samenrotting
which samenrotting?welke samenrotting?
a big samenrotting / the big samenrottingeen grote samenrotting, de grote samenrotting