(Compound annuity) What is the accumulated sum of each of the following streams of payments? a. $500 a year for 9 years compounded annually at 11 percent. b. 5104 a year for 7 years compounded annually at 9 percent. c. $36 a year for 13 years compounded annually at 12 percent. d. $24 a year for 4 years compounded annually at 5 percent. a. What is the accumulated sum of $500 a year for 9 years compounded annually at 11 percent? (Round to the nearest cent.)