I have been trying to find the answer to this problem for hours. The production possibilities frontier illustrates Select one:

I have been trying to find the answer to this problem for hours. I've tried every possible one and it isn't working please help me.The production possibilities frontier illustratesSelect one:a. the combinations of output that an economy should produce. b. the combinations of output that an economy should consume. c. the combinations of output that an economy can produce. d. all of the above