See the following incomplete pension spreadsheet. What was the firm's pension expense? Prior Net Plan ($ in millions) PBO Service Cost Loss/Gain Pension Expense Cash Assets -AOCI -AOCI Beginning Balance 400 cr. 450 dr. 60 dr. 55 dr. Service Cost 85 cr. Interest Cost 25 cr. Exp. Return on Assets 55 dr. Amortization of: Prior Service Cost Net Loss 1 cr. Abn. Return on Assets 3 dr. Loss on PBO 65 cr. Contributions to Fund 40 dr. Retiree Benefits Paid Ending Balance 530 cr. 54 dr. 122 dr. Oa. $72 million b. $62 million $67 million $56 million d. O O $85 million e