William, age 55, wants to retire at age 65 with $2,000 in monthly retirement income. He currently participates in his company's 401(k) plan, but also is a member of a union whos retirement plan will provide him with $1000 monthly, William is assuming he will live until age 95 and does not want you to consider any Social Security benefits in his retirement income computation. If the return in the company's 401(k) plan is 10% annually what monthly amount does William have to contribute to that plan for 10 years to meet his retirement income objective?

a) $556

b) $747

c) $1113

d) $2000