Explain how each of the following will affect the net public debt, other things being equal. a. Previously, the government operated with a balanced budget, but recently there has been a sudden increase in federal tax collections. The net public debt ▼ increases remains unchanged decreases . b. The federal government had been operating with a very small annual budget deficit until three successive hurricanes hit the Atlantic Coast, and now government spending has risen substantially. The net public debt ▼ increases remains unchanged decreases . c. The General National Mortgage Association, a federal government agency that purchases certain types of home mortgages, buys U. S. Treasury bonds from another government agency. The net public debt ▼ increases decreases remains unchanged .