need help on this one please

4. Burr Co. made a plan amendment on 1/1/2021 granting $40,000 of retroactive benefits to employees recorded as prior service costs. Relying on the average remaining service years, Burr Co. determines that $8,000 of prior service costs should be amortized. What is the 2021 financial statement impact of these transactions? a. Decrease pension expense by $8,000; increase the PBO by $40,000 b. Increase pension expense by $8,000; decrease the PBO by $40,000 c. Increase pension expense by $8,000; increase the PBO by $32,000 d. Increase pension expense by $8,000; increase the PBO by $40,000 e. Decrease pension expense by $8,000; decrease the PBO by $32,000