The following data relate to a defined benefit pension plan for Hollistir Co. Fair value of plan assets, Jan. 1, 2020.. PBO Jan. 1, 2020, not including any items below PSC from amendment dated Jan. 1, 2020, (10 years is the amortization period). Gain from change in actuarial assumptions, computed as of Jan. 1, 2020 Actual return on plan assets, 2020.. Contributions to plan assets in 2020 Benefits paid to retirees in 2020. Service cost for 2020 .... Discount rate Expected rate of return on plan assets.. $16,000 20,000 10,000 3,000 2,000 4,000 5,000 9,000 8% 10% Required a. Compute pension expense for 2020. Hollistir amortizes the full pension gain/loss over average service life of 15 years, using the straight-line method. b. Compute the PBO at December 31, 2020. C. Compute fair value of plan assets at December 31, 2020.