Resolves Yes if both of them do not take part due to any reasons.
Resolves No if at least 1 of them participates.
Related questions
[Deleted]
This means the focal point thing: whether they will be candidates in the upcoming elections (or whether both drop out). Resolves the day after elections.
It cannot resolve no, because elections have not happened yet. Even if the question had "preelection procedures" instead of "election" - Biden is not even nominated by democratic party at the moment.
I use common sense here. If the person is dead - he is not participating. If his his name is not on ballots, then he is not participating.
What if none of them are on the ballet, but at least 1 person still writes in their name?
That is irrelevant to the question, actions of voters do not matter. We can invent infinity of such silly cases. Not even going to start to add them. If you do not understand what the question asks about - you are welcome not to bet.