Find the present values of these ordinary annuities. Discounting occurs once a year. Do not round intermediate calculations. Round your answers to the nearest cent. a. $500 per year for 12 years at 12%. b. $250 per year for 6 years at 6%. C. $200 per year for 6 years at 0% d. Rework previous parts assuming they are annuities due. Present value of $500 per year for 12 years at 12%:$ Present value of $250 per year for 6 years at 6%:$ Present value of $200 per year for 6 years at 0%:$