Exercise 20-21 Riverbed Inc. provides the following information related to its postretirement benefits for the year 2017. Accumulated postretirement benefit obligation at January 1, 2017 Actual and expected return on plan assets Prior service cost amortization Discount rate Service cost $694,700 33,100 20,800 9% 84,000 Compute postretirement benefit expense for 2017. Postretirement benefit expense Click if you would like to Show Work for this question: Open Show Work