In a certain economy, toys and greeting cards are produced, and the economy currently operates on its production possibilities frontier. Which of the following events would allow the economy to produce more toys and more greeting cards, relative to the quantities of those goods that are being produced now?
a. The economy experiences economic growth.
b. There is a technological advance in the toy industry, but the greeting card industry experiences no such advance.
c. There is a technological advance in the greeting card industry, but the toy industry experiences no such advance.
D. All of the above are correct.