The term "automatic stabilizers" refers to the fact that:（）

A. legislators automatically change the tax structure and expenditure programs to correct upswings and downswings in business activity.

B. with given tax rates and expenditure policies, a rise in national income tends to produce a surplus, while a decline tends to result in a deficit.

C. government expenditures and tax receipts automatically balance over the course of the business cycle, although they may be out of balance in any single year.