Path A: Wales would defeat Austria and Ukraine would do the same against Scotland. And after a Wales - Ukraine matchup, Wales would manage to qualify for the World Cup.
Nothing against Wales, but I think Ukraine's probability of victory is much higher than that of Wales. Wales have good players, but even so I think Ukraine is more likely to reach the World Cup than Wales. If Wales makes it, it's history for them.
In fact, I agree with you, but the bookmakers have a diametrically opposite opinion:
Austria 3.00
Wales 3.50
Scotland 3.75
Ukraine 4.50
Ukraine is considered an outsider of the A. In my opinion, this is an underestimation of Ukraine and perhaps it makes sense to bet on it, although I have no desire to freeze money for such a long period.