What is the role of the government in fiscal policy

Everything.

Explanation:

The fiscal policy is used to define the revenue of the government, and it shows if the government saved money (spent less than received through taxes, loan returns, etc.), or spent more than their budget (a deficit). This would affect the policy of the next year, and may give rise to either a deduction of benefits to the US population or an increase. Of course, there may be changes to other governmental expenditure, such as military build-up or deregulation, industrial build-up, etc.

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increase in population

i believe the correct answer is b.