Ben Bakes Bread and Shawna Knits Sweaters

Multiple Choice

Ben bakes bread and Shawna knits sweaters.Ben and Shawna both like to eat bread and wear sweaters.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) Both Ben and Shawna can benefit from trade in all of the above cases.