Twins Amanda and Daniel invest in mutual funds. Amanda majored in fi nance. For more than 20 years she invested in managed funds, counting on intelligent professional fi nancial advisers to select the winning companies more often than not. Daniel majored in English; he invested in unmanaged index funds that achieve the same return as a particular market index by buying and holding all or a representative selection of securities in the index. After 20 years of investing, what is the likelihood that Amanda’s investment portfolio balance will be better than Daniel’s?

A. 10%

B. 20%

C. 30%

D. 40%