Well, the best bet would be to avoid getting into a situation where you need to use the OS option. Step one is to PAY ATTENTION to what is around you and what you are doing. In all the years I have lived and worked and played in the woods, including four years around Yellowstone, I NEVER have been in a bad situation with a bear.

And, frankly, the odds of you getting attacked by bear, unless you are doing something stupid, are so slim as to not be worth worrying about. Worry about a car accident, falling in the bathtub, clogging your arteries, or all the other ways people actually die. Amazingly, one never sees discussions in here about how to avoid a drunk driver on the way to the river. Or about bees, which kill far more people every year than large carnivores. Or white-trailed deer.

I always advise against carrying a handgun (aside from the legal issues) because, frankly, 95% of people wouldn't be able to recognize the situation, draw the weapon, and get off a shot before they got flattened anyway. And of the ones who did, few would hit the bear. It takes training to be able to use a handgun instantly and effectively, and nobody who doesn't get paid to do so trains that well.