In core-plus bond management, O a. 75 percent of the portfolio is allocated to actively managed bond sectors, and the balance is allocated to a foreign bond index. O b. 75 percent of the portfolio is allocated to actively managed bond sectors, and the balance is allocated to a bond index. O c. 75 percent of the portfolio is allocated to an equity index and the balance is allocated to a bond index. O d. 75 percent of the portfolio is allocated to a bond index, and the balance is allocated to actively managed bond sectors. O e. 75 percent of the portfolio is allocated to a bond index, and the balance is allocated to an equity index.