De or het transportfirma?

The correct Dutch article is:

de transportfirma

How to use transportfirma

the transportfirmade transportfirma
this transportfirmadeze transportfirma
that transportfirmadie transportfirma
our transportfirmaonze transportfirma
your transportfirmajouw transportfirma
every transportfirmaelke transportfirma
which transportfirma?welke transportfirma?
a big transportfirma / the big transportfirmaeen grote transportfirma, de grote transportfirma