Determining Obligations for Postretirement Benefit Plan reaching age 62. Expected benefits are $15,000 per year for an estimated 10 years commencing at an estimated retirement age of 67 years. a. Calculate the attribution period. years b. Calculate the expected postretirement benefit obligation (EPBO) on January 1 of Year 5 , using an interest rate of 6%. - Note: Round your answer to the nearest whole dollar. c. Calculate the accumulated postretirement benefit obligation (APBO) on January 1 of Year 5, using an interest rate of 6\%. - Note: Round your answer to the nearest whole dollar