Macroeconomics 20th Edition by Campbell McConnell ,Stanley Brue ,Sean Flynn

Exercise 3

Suppose that an economy begins in long-run equilibrium before the price level and real GDP both decline simultaneously. If those changes were caused by only one curve shifting, then those changes are best explained as the result of:
A) The AD curve shifting right.
B) The AS curve shifting right.
C) The AD curve shifting left.
D) The AS curve shifting left.