What is a bank?

I either get an 0% or 100%

Hours to produce one unit worker hours to produce yarn country a 8 hours country b 4 hours worker hours to produce fabric counrty a 12 hours country b 13 hours additional worker hours to produce fabric instead of yarn country a ? country b? which of the follow is true of the trade relationship between country a and country b? country a has an absolute advantage in producing yarn and fabric country b has an absolute advantage in producing yarn and fabric country b has a comparative advantage to country a in producing fabric country a has a comparative advantage to country b in producing fabric