Likely 1 is common but there is only one way to be sure that's to test switch. The larger switches tend to be rotary using a cam. The switch also likely a sandwich of a number of wafers all linked together. The profile of the cam and the way the wafers are joined can produce any number of different options. So guessing is really no good you just need to test switch.
Normally the earth is either connected to the back box, linked to outgoing cable, or when all is double insulated folded back on it's self and some earth sleeve slipped on it for future use if switch changed.
The earth is never switched. The only time an earth is removed is for testing.
With plastic switches it's common to have no earth connection. Do remember you have given no clue to size or type of switch so it is only a general reply.