A "D" passport is a is a poor travel document that mainly provides access to some countries of Latin America and South East Asia. A “C-” passport does NOT provide access to the Schengen area or most of the developed world.
To receive a "D" grade, a passport must have a Travel Freedom score (Passport Score) between 23 and 37.
Additional Analysis:
The Travel Freedom score of this passport is at least 50% lower than its simple count of visa-free countries. It means that this passport provides access only to countries that are not attractive.