C. Separation of powers although I guess it also ties in with checks and balances and the branches of the government
The PPC (or PPF, same thing) shows economic growth because it outlines exactly what the economy can produce at that moment. When it shifts outward in any way (be it towards consumer and capital goods, or X and Y), that MUST be because of economic growth.
The first branch produces... or (i forgot its name) branch. It makes the law idea. The new law then goes to the approval branch. They either vote it good, or trash it. If it is good, then it goes to the supreme court where the law is checked over by the judges and law members to make sure it follows the constitution. If they approve it, it becomes a law...
