Self-determination is the right of a people to determine its own destiny. In particular, the principle allows a people to choose its own political status and to determine its own form of economic, cultural and social development.
The Brexit is an example because they determine themselves how the future is going to be in the form of politics and economy.
It would be the last one. All male citizens could vote in the city assembly regardless of wealth. To be a citizen in the Athenian democracy, you have to be a free white male.
