It's all swings and roundabouts

I'm trying to get a better handle of the British (and possibly other type of world English) idiom "it's all swings and roundabouts" since I'm getting slightly conflicting answers from the google gods. Is it...

a) It all evens out in the end.
b) It doesn't matter (because 'What you lose on the swings, you gain on the roundabouts')
c) Six of one, a half dozen of the other
d) none of the above

It is (b).

Swings (suspended seats which swings back and forth) and roundabouts (small merry-go-rounds pushed by hand) are commonly found in children's playgrounds. I usually think of it as saying it doesn't matter whether you play on one or the other, they are both fun. As an idiomatic phrase it is used when a choice presents itself in the process of doing something, but appears largely unimportant to the final goal.

Thanks for your help.

Wow. Never heard that expression before. I was kind of guessing that a roundabout might be a merry-go-round, but I was thrown off by the traffic circle meaning, too -- and I would never have been able to guess the idiomatic meaning, of course.