Etymology of Afghan?

Factual Questions
1

Pashto? Farsi? Turkic? Chinese?

Any ideas???

2

The normally reliable Brewer is a touch vague about this one, saying:

Afghanistan: The central Asian republic derives its name from its native inhabitants, the Afghanis, with the latter part of the name representing the Old Persian stan, ‘country’ (ultimately related to the English ‘stand’). The people’s own name comes from Afghana, a Persian word that may be the name of one of their ancestors.

3

Some more information from the Encyclopedia Britannica:

4

And the American Heritage Dictionary agrees that afghan comes from Persian.