Question

if there is a national debt, we can conclude that the federal government has
purchased more goods and services than were needed.
loaned funds to other nations in the past.
borrowed in the past.
loaned funds to u.s. taxpayers in the past.
spent money foolishly.

Explanation:

National debt is the total amount of money that a federal government owes to creditors. This debt accumulates when the government borrows funds (for example, by issuing bonds) to cover budget shortfalls in previous periods. The other options are incorrect: over-purchasing goods does not directly equal debt, lending funds would create assets not debt, and "foolish spending" is a subjective judgment not a definitive cause of debt.

Answer:

borrowed in the past.