Calculate the present value of each of the following future payments.
a. A $10,000 lump sum received 2 years from now if the market interest rate is 10 percent
b. A $1,000 lump sum received 3 years from now if the market interest rate is 5 percent
c. A $25,000 lump sum received 1 year from now if the market interest rate is 12 percent
d. A perpetuity of $500 per year if the market rate of interest is 6 percent