8. The accumulated benefit obligation measures a. the pension obligation on the basis of the plan formula applied to years of service to date and based on existing salary levels. b. the pension obligation on the basis of the plan formula applied to years of service to date and based on future salary levels. c. an estimated total benefit at retirement and then computes the level cost that will be sufficient, together with interest expected to accumulate at the assumed rate, to provide the total benefits at retirement. d. the shortest possible period for funding to maximize the tax deduction