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、BencannotknitsweatersandShawnacannotbakebread.;
B、BenisbetterthanShawnaatbakingbreadandShawnaisbetterthanBenatknittingsweaters.;
C、BenisbetterthanShawnaatbakingbreadandatknittingsweaters.;
D、BothBenandShawnacanbenefitfromtradeinalloftheabovecases.