Question

U.s. national debt​ ______ when the federal​ government's ______.

Answer 1

d. Increases when outlays (payments) exceed revenue.

Outlays (or payments) are the expenses, and tax revenue is the income. So whenever the expenses outweigh the income you will add to the debt. If you earn $500 a month but spend $700  you will be adding that extra $200 to your debt each month.