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. $800 per year for 16 years at 12%. $ b. $400 per year for 8 years at 6%. $ c. $500 per year for 8 years at 0%. $ d. Rework previous parts assuming they are annuities due. Present value of $800 per year for 16 years at 12%:$ Present value of $400 per year for 8 years at 6%:$ Present value of $500 per year for 8 years at 0%:$