($ in millions) debit (credit) PBO Plan Assets Prior Service Cost Net (Gain) Loss Pension Expense Cash Net Pension (Liability) Asset 450 60 55 50 (85) (25) 55 3 Beginning balance Service cost Interest cost Expected return on assets Gain/loss on assets Amortization of: Prior service cost Net gain/loss Loss on PBO Contributions to fund Retiree benefits paid Ending balance (1) (65) 40 (530) 54 122 What was the PBO at the beginning of the year? A. $160. B. $400. O C. $500. O D. $610. What were the retiree benefits paid? A. $45. B. $50. O C. $55. O D. $60