Consider two individuals — Marquis and Serena — each of whom would like to wear sweaters and eat tasty food. The gains from trade between Marquis and Serena are most obvious in which of the following cases? a. Marquis’s cooking and knitting skills are very poor, and Serena’s cooking and knitting skills are also very poor. b. Marquis is very good at knitting sweaters and at cooking tasty food, but Serena’s skills in both of these activities are very poor. c. Marquis and Serena both are very good at cooking tasty food, but neither has the necessary skills to knit a sweater. d. Marquis’s skills are such that he can produce only sweaters, and Serena’s skills are such that she can produce only tasty food.