Boots B would look cute with dresses and shorts. Boot A looks more realistic though, better for walking about. Even little heels end up hurting the feet eventually lol. Not really a fan of dark brown, I'd go for something a little lighter or just straight up black.
I like Boot B, but only because that's a completely timeless look that can be worn on any occasion and would also be appropriate for work. Boot A has more style to it with the bands around the top of the boot.