Ben Bakes Bread and Shawna Knits Sweaters

Ben bakes bread and Shawna knits sweaters.Ben likes to eat bread and wear sweaters,and the same is true for Shawna.In which of the following cases is it impossible for both Ben and Shawna to benefit from trade?

A) Ben cannot knit sweaters and Shawna cannot bake bread.
B) Ben is better than Shawna at baking bread and Shawna is better than Ben at knitting sweaters.
C) Ben is better than Shawna at baking bread and at knitting sweaters.
D) None of the above is correct.