Pollution taxes are more efficient in cleaning up the environment than direct controls. What is not an advantage of direct controls? a. They are useful where dependable metering devices are not available or prohibitively costly to install.
b. They are useful if it is decided to prohibit the substance altogether.
c. They are most useful in centrally planned economies.
d. They are useful standby mechanisms.

Assume that the following conditions exist: a. all banks are fully loaned up- there are no excess reserves, and desired excess reserves are always zero. b. the money multiplier is 5 .     c. the planned investment schedule is such that at a 4 percent rate of interest, investment =$1450 billion. at 5 percent, investment is $1420 billion. d. the investment multiplier is 3 . e.. the initial equilibrium level of real gdp is $12 trillion. f. the equilibrium rate of interest is 4 percent now the fed engages in contractionary monetary policy. it sells $1 billion worth of bonds, which reduces the money supply, which in turn raises the market rate of interest by 1 percentage point. calculate the decrease in money supply after fed's sale of bonds: $nothing billion.