Stone Corporation has a defined benefit pension plan. One of its employees has vested benefits under the plan, which will pay her $30,000 annually for life starting with the first $30,000 payment on the day she retires at the age of 65. The employee has just reached the age of 45. Stone consulted standard mortality tables to come up with a life expectancy of 80 for this employee. The implicit interest rate under the plan is 9%. Required: To fulfill this pension obligation, what amount does Stone Company need to have at the time of th employee's retirement (what is the present value of the retirement benefit at the time the employee retires)? a. $600,000 b. $450,000 c. $263,585 d. $241,821