Answer:
a. Decrease
If the Federal government increases taxes on people, they will have less money to spend and save after paying their taxes. This will reduce their consumption and investment (savings) thereby leading to a lower aggregate demand.
b. Increase
An increase in the money supply means that people will have more money to spend on goods and services. They will therefore consume more. More money in the economy reduces interest rates so people will borrow to invest more as well. These two things will combine for an increase in aggregate demand.
c. Increase
If consumers are more confident about their economy, it means they find it safe to invest in it. As they invest, the investment component of aggregate demand would rise which would increase aggregate demand.
d. Decrease
The oversupply from recent years will mean that investment required in recent years will be less. This will lead to a lower aggregate demand.