Not everyone is a bike mechanic or aspires to be. I thought I asked a fairly simple question about what gear system would make the most sense for the stated riding I mentioned in my initial post. Telling me what you did, in bike mechanic terms, doesn't really tell me if I'd be ahead with a 2,3, or 6 speed riding on paved paths with rather gentle inclines. I note on my 27 speed MB that I rarely use more than 3-4 gears and am almost never out of the middle chain ring. That's what got me to thinking about which gearing really makes the most sense *for me*.
For the gears you use on your MTB: stop the bike and count the teeth on the front and rear cogs (chainwheels) on the combinations you use often on your MTB.
Go to the online gearcalculatot and plot in the numbers (one combination at the time) plus wheel size and the other stuff that the calculator wants to know.
Do the same for the gears
available on your B. This info is needed to answer your question.