The B kit with one less roller should be it. The extra roller goes down by crank sprocket and at least earlier Foci had the holed drilled and tapped for it. They did not come with it though, more like earlier engines like zetec in '98-'00 Contour used it. You can leave it off, the cams just time slightly differently to make up for the slight length difference in track there.
I used to buy the A kit to get the extra bearing in the unused roller which cuts out of the plastic pretty easy, can use it like in rebuilding serp belt idlers, as well that kit was at least before MUCH cheaper with the added part, but looks like they've discovered that and bringing prices more in line with each other now.
EITHER kit will work. Just don't use the unneeded idler.