Don't be distracted by the guy who has a seizure behind you, unless you're qualified to treat him. They won't give you any bonus points for the interruption. Try to ignore it.
Take a multivitamin tonight, and tomorrow AM. Couldn't hurt.
The answer is almost never E.
B or C if you don't have a clue.
Get some sleep. Try meditation before bed.
Relax. You've done all you can. You'll do fine.