I consider two possible options that I can choose now:
Either meeting with the prosecutor (option 2) or trial option (option 3).
A question about option 2:
If I choose this option, will my fine be reduced and will demerit points not be added to my record?
Most prosecutors are pretty flexible if a) the speed wasn't excessive b) your record isn't lousy.
Best bet is if the speed was reduced, option 2, if not you're stuck cause if you go to court it'll likely be amended back to the full speed.