Answer: automatic stabilizer.

The correct answer is **A** because a decline in tax revenues during a recession exemplifies an automatic stabilizer. Automatic stabilizers adjust the budget deficit without deliberate fiscal policy changes. During a recession, reduced tax revenues naturally increase the budget deficit. - **Option B (Incorrect)**: Expansionary fiscal policy involves deliberate government actions, such as increased spending, to stimulate the economy during a downturn. This is distinct from automatic stabilizers, which operate without discretionary intervention. - **Option C (Incorrect)**: Contractionary fiscal policy is a discretionary measure, typically involving reduced government spending or increased taxes, to cool an overheating economy. It is unrelated to the automatic adjustments seen in tax revenues during a recession.

Author: LeetQuiz Editorial Team