Option A is more preferable to me. It would be fate set in stone. It's possible to plan around it. Work extra overtime and make a grand exit in the last month or so.
I wonder, if you know when and you can't change it; wouldn't that mean you are in a way invincible up to that date?
Option B would be very stressful and haunting. IMO it's human nature to try to prevent it from happening if you know how; even if you couldn't change it.
Dying in your sleep could mean a person would be too afraid to go asleep; but no sleep eventually also leads to death.
