De or het postcommunie?

The correct Dutch article is:

de postcommunie

How to use postcommunie

the postcommuniede postcommunie
this postcommuniedeze postcommunie
that postcommuniedie postcommunie
our postcommunieonze postcommunie
your postcommuniejouw postcommunie
every postcommunieelke postcommunie
which postcommunie?welke postcommunie?
a big postcommunie / the big postcommunieeen grote postcommunie, de grote postcommunie