Find the present values of these ordinary annuities. Discounting occurs once a year. Round your answers to the nearest cent. a. $500 per year for 12 years at 8%. b. $250 per year for 6 years at 4%. C. $1,000 per year for 10 years at 0%. Rework previous parts assuming that they are annuities due. Round your answers to the nearest cent. d. $500 per year for 12 years at 8%. e. $250 per year for 6 years at 4%. f. $1,000 per year for 10 years at 0%. $