What is "Unsupported Cable Assembly"

While studying the material on Electrical Inspections the quiz question is: Unsupported cable assemblies ______ acceptable in crawlspaces only.

Answer: “Not Allowed”

In my experience with modern homes where we only used conduit (no NM wires) I need help understanding the term: “Unsupported Cable Assembly”. Does this refer to NM wires?

And what would be the rationale for them being allowed in a basement, but not allowed in a crawlspace?

Cables need to be supported regardless of the location. NM is required to be secured at intervals of no more than 4.5’.

Only cables of a certain size are allowed below the joists. Smaller cables need to be through bored holes or on running boards.

Thanks Jim.
What do you think the quiz question was trying to teach us? I am missing the point because I did not see the phrase “Unsupported Cable Assembly” in the instructional material. The question implies that we can allow something different in the crawl than other places like a basement.

“Unsupported Cable Assembly” is not in the NEC either.

Many times I have seen wiring laying on the floor of the crawl space, instead of being properly supported overhead.
And there have been times when the wiring, that was laying on the floor of the crawl space, was actually running through pools of water.
I didn’t write the question, but this is what came to mind when I read it.