None of the above. Keep guessing. lol. Actually I had the answer but I forgot it. I think it is the Record Date. It has to be a couple of days before the Record Date otherwise they can't set the ex-date one day before it. That's why I forgot it, because it didn't make 100% sense to me.
But as you know, there is a reason for the deferred ex-dates. Let me look it up for you.