[Answer] Which of the following statements about the production possibilities frontier is true?I. It can show the impact of a change in technology on production decisions.II.It can graphically illustrate the concept of scarcity.III. It allows us to see the concept of under-employment and full employment.IV. It shows the concept of trade-offs and opportunity cost.II and IV onlyI II and IV onlyI II and III onlyII III and IV onlyI II III and IV