A managed fund run by Closeburn Investments Ltd is offering a rate of return of 6% per annum, compounded semi-annually, after fees. If Henrietta deposits $10,000 in this fund, how many years will it take for her to double her investment?

Select one:

a. 10.7 years

b. 23.4 years

c. 11.7 years

d. 21.4 years