Over the last ten years productivity grew faster in Oceania than in Freedonia and the population and total hours worked remained the same in both countries. It follows that:
a. real GDP per person must be higher in Oceania than in Freedonia.
b. real GDP per person grew faster in Oceania than in Freedonia.
c. the standard of living must be higher in Oceania than in Freedonia.
d. All of the above are correct.