Why are fiscal policies sometimes difficult to use in regulating the economy?

A) ?Federal spending cannot be easily adjusted up or down as economic conditions change.
B) ?Decisions about how much government should spend are made by a very small group of people.
C) ?Changes in spending and taxes can occur very quickly before many economists can agree on what the problem is.
D) ?Decisions by Congress to lower the discount rate to federal banks are a cumbersome process.
E) ?Checks and balances provided for in the Constitution require agreement among all three branches regarding a course of action.

A