Sherin Blake, owner of Blake Architectural Design, Inc. has hired an actuary to calculate the funding requirement for the company's defined benefit plan. To make an accurate calculation, the actuary will have to consider:

a. the estimated retirement age of all employees covered by the plan

b. the formula that Sherin chose to use to calculate employee retirement benefits

c. interest earnings on the fund

d. all of the above

e. only a and b