The network would either fragment or die. Depending on how many local/regional networks still exist or are brought up, there would be too many forks to count an

The network would either fragment or die. Depending on how many local/regional networks still exist or are brought up, there would be too many forks to count and then any spends are impossible to really rely on, or just no stable forks at all. You can sign things offline, sure, but you can't really verify them. I could spend the same coins a thousand times if the people accepting them can't reliably check for verifications using the same consistent chain. I don't even understand how the scheme in "c" would work to be honest, and I have a decent background in crypto and cryptocoins. How many people are going to be able to make that work? I just can't see any of that happening. I'd expect a combination of a barter economy, some precious metals and whatever physical currency is around.