What is the shape of the long-run supply curve in a decreasing-cost industry?

In the figure above, suppose that Mac and Izzie trade and reach point c. Then

A) Mac produces outside his production possibilities frontier. B) Izzie produces outside her production possibilities frontier. C) Mac and Izzie both produce outside their production possibilities frontiers. D) neither Mac nor Izzie produce outside their production possibilities frontiers.

Refer to Table 8-8. Suppose that a simple economy produces only four goods and services: sweaters, CDs, sugar, and soft drinks

Assume one half of the sugar is used in making the soft drinks and the other half of the sugar is purchased by households. Calculate nominal GDP for this simple economy.