I would go with A) personally. I honestly don't think it would be fair to punish people that haphazardly invested in it....as I'm assuming most did before they were told that it wasn't supposed to be there.

C) is way too excessive unless people were exploiting it on purpose. If that were the case, I would rather use option B on those individuals.

I would prefer they just disable the boost (if any) that they are receiving. I have no doubt that it is an option to simply remove any buffs utilized through that system.

Still no reply from moderators?

It's not "Taking Advantage" when people didn't know that the said feature is a Bug that went live along with other features of version 5.0 .. Some people just got so excited and jump right into it , spending their resources and get power .. Since it is noted and included in the version 5.0 website .. So, your option B is too much, not all the players who purchased or spend on that feature is p2ws, some of them are f2ps who saved and collected coupons to get power ..

Better options for this issue is your option A .. if not, then make a statement and proof that they deactivated the feature even tho it shows in the character's info ..

Remember, they only posted a thread stating that the said feature is a bug after minutes of it being live in in the game .. anything can happen within 1 min and that 1 min is not taking advantage specially if the person didn't know it was a bug ..

Ignorance is not relevant to the situation as the Feature popped-up together with the Updated .. The mods took action of posting a thread minutes ago after the Servers got back online .. Your option B can only be applied to those people who spent in that feature after the Mods posted a notice about the said feature .. I was here and in discord during that time, that's why i know the gap of time of the Server-up and the time of acknowledgement that the said feature is a bug ..