Consider Two Individuals, Jarek and Danuta Each of Whom Knits

Consider two individuals, Jarek and Danuta each of whom knits sweaters and makes hamburgers, respectively. The gains from trade between Jarek and Danuta are most obvious in which of the following cases?

A) Jarek is very good at knitting sweaters and at making hamburgers, but Danuta's skills in both of these activities are very poor.
B) Jarek and Danuta both are very good at making hamburgers, but neither has the necessary skills to knit sweaters.
C) Jarek's cooking and knitting skills are very poor, and Danuta's cooking and knitting skills are also very poor.
D) Jarek's skills are such that he can only knit sweaters, and Danuta's skills are such that she can only make hamburgers.