Figure 2-9 -Which of the Following Statements Could Explain the Concave Shape

Figure 2-9

-Which of the following statements could explain the concave shape of the production possibilities curve in Figure 2-9?

A) The publishing industry develops improved printing presses.
B) Productive efficiency increases as the publishing industry moves from point F to point H
C) More editors and writers are employed as the publishing industry moves from point F to point H.
D) Some writers are better suited to writing novels;some are better suited to writing textbooks.
E) The prices of paper and ink fall as the publishing industry moves from point H to point F.