A budget deficit is defined as:

a. a shortfall of revenues compared to expenditures.

b. a shortfall of expenditures compared to revenue.

c. accumulated deficits minus accumulated surpluses.

d. accumulated surpluses minus accumulated deficits.

The correct answer to the given question is option a. a shortfall of revenues compared to expenditures.

A budget deficit usually occurs when the revenues are less than the expenditures or the expenditures are more than the revenues. Such deficit is usually financed by raising debt or loans. For a given economy, the government usually expresses the budget deficit as a percentage of the GDP (Gross Domestic Product).