Dr. Stein has just invested $10,000 for his son (age 7). The money will be used for his son's education 10 years from now. He calculates that he will need $25,940 for his son's education by the time the boy goes to school. What rate of return will Dr. Stein need to achieve this goal? Select one: 8% 2% 11% 10% 9% 7%