A portfolio is comprised of three index funds: an equity index comprising 40% of the total portfolio, a bond index comprising 30% of the total portfolio and an international index comprising 30% of the total portfolio. After each quarter the portfolio manager buys and sells some of each sector so as to preserve the original weights for each sector. This is an example of ____________.
a. a passively managed core with an actively managed component
b. a totally passively managed fund
c. passive asset allocation with active security selection
d. active asset allocation with passive security selection