In the article, they use the term "domestic" to refer to a Pakistani agency posting in Pakistan. The definitions are slightly more clearly explained in another post[0]:

> Foreign-led efforts to manipulate public debate in another country

So it seems to be the nation whose public debate is being targeted, meaning that it could theoretically be either 2 or 3 depending on the intentions of the actor and Facebook's ability to discern it, but definitely not 1.

0: https://about.fb.com/news/2019/10/inauthentic-behavior-polic...