6. Ruth H. wants to build a house in 12 years. She estimates that the total cost will be $350,000. If she can put aside $20,000 at the end of each year, what rate of return must she earn in order to have the amount needed, assuming annual compounding?

A. Between 11% and 12%

B. Between 8% and 9% C. 17%

D. 6.63%