I don't know what is meant by statement B).
I have entered the Free Zone from Belize and returned to Belize.

Maybe to clarify... the Free Zone is actually situated on land immediately south of the Hondo River (the Hondo River being the border between Mexico & Belize), AND sitauted between the Mexican & Belizean border control points.

So, to get to the free zone from Mexico, you go through Mexican customs/immigration (exiting Mexico), cross the bridge over the river and enter the free zone.

To get to the free zone from Belize, you go through Belizean customs/immigration (exiting Belize), and then enter the free zone.

I've been to the zone twice, and the most I spent was a few $ for lunch. Don't think I'd ever go again.