First of all, nobody knows what “the electorate” was, because the electoral register was opaque and dubious. The separatist government has been accused of obtaining the census via illegal means, and of compiling the electoral register in secrecy, without any accountability. Was everyone born in Catalonia, but living elsewhere, called to vote? Were all residents (those “empadronados” in Catalonia) called to vote? Who was allowed to vote by mail, and did that actually work properly? Did the electoral register include minors too (who are not allowed to vote in any democratic process in Spain), like it did in the previous farce of a referendum, three years ago?

At this point, we can’t trust any official numbers.

Anyway, let’s assume abstention was at 58% as you say — for the sake of argument. For reference, in the last general elections in Spain, abstention was at 30%. That’s a “normal” level, so it isn’t unfair to assume a similar level of laziness or apathy in this “referendum”. This is case “A” for you. That leaves us with just an extra 28% of abstention to account for.

I can totally see that remaining 28% of the “the electorate” either choosing to boycott the bogus referendum (your case “C”); deciding to comply with the ruling by the Constitutional Court, being too afraid of the police and of violence in the streets, or simply being prevented from voting because there were no open polling place, no ballots or no ballot boxes (all those are your case “B”). Throw in a certain amount of intimidation in polling places, and meddling by those in charge of the recount, and we can explain more abstention. All these are “rational explanations” to explain the “missing votes”.

My point is: all these figures don’t mean anything at all. The separatists can’t use them to prove popular support because the whole thing was illegal and biased from the beginning, there was no campaign for the “no”, and footage and testimonies show all kinds of irregularities and meddling in the process. The Spanish government can’t use them to prove that the majority of Catalans are against independence because, well, it put all kinds of obstacles (legal and physical) in the way of the “referendum” in the first place.