Not an option on humanitarian grounds. (I know, dirty words)
The Afghans - the regular ones, not the Talis - are neutral to fine with Brits, Aussies and Americans. They all hate Russians passionately though and Russia going in will lead to a ridiculous death toll.
There's only two mainstream options with Afghanistan:
1/ Walk away. The worst of the terrorist nests are cleared out, so leave and let them sort out their own problems.
2/ Increase forces and basically do a house to house purge of the entire country, then make them a protectorate until they get something approaching a functional system going. I'm not saying a western style democratic system, necessarily, but something that works.
Neither option is particularly appealing, especially with the mountains (there's not really such a thing as a border between Afghanistan and Pakistan, it's more like a separate client nation of both bigger nations).
There is a third option which is never talked about:
3/ Partition. Split the country into it's three more or less autonomous regions and pick one to support, a la Yugoslavia. Horrible optics as far as international politics goes, but it's workable. Might even ease tensions off in Kashmir if Pakistan has an opportunity to expand it's legal influence north and west.