Suppose a defined-benefit pension plan offers a retirement benefit tied to years of service and final salary and that the retirement benefit is increased by a fixed 5% per year each year.There is a plan to change the retirement-plan formula so the amount of the retirement benefit increase is positively correlated to how companys stock has performed (rather than the fixed 5% rate).The change in this retirement will cause the discount rate for the DB plan benefit to:

a Increase

b Stay the same

c Decrease