For the Following Questions, Use the Diagram Below

Multiple Choice

For the following questions, use the diagram below:
Figure 21-7.
-Refer to Figure 21-7. Which of the following is correct?

A) A wave of optimism could move the economy from point a to pointB
B) If aggregate demand moves from AD₁ to AD₂, the economy will stay at point b in both the short run and long run.
C) It is possible that either fiscal or monetary policy might have caused the shift from AD₁ to AD₂.
D) All of the above are correct.