You are evaluating mutual funds for investment in your $401k$ retirement plan. Based on the characteristics presented, indicate whether each manager is employing a passive index$-$based strategy, an enhanced index strategy, or a fully active investment strategy.

All managers are compared to the Barclay's U$.$S$.$ Aggregate Bond index, which have the following characteristics:

Duration $=5\mathrm{.}5$ years; Credit quality $=A$ A; Treasuries $40\%,$ Securitized $($Mortgage$-$backed$)30\%,$ Corporates $30\%$

No global securities$.$ No securities below investment grade.

Manager $1$: Duration $6\mathrm{.}5$ years; Credit quality BBB; Treasuries $10\%,$ Securitized $($Mortgage$-$backed$)20\%,$ Corporates $70\%$ including up to $20\%$ 'high yield' $($below investment grade$)$

Manager $2$: Duration $6\mathrm{.}0$ years; Credit quality AA; Treasuries $20\%,$ Securitized $($Mortgage$-$backed$)30\%,$ Corporates $30\%$ including up to $5\%$ 'high yield' $($below investment grade$)$

Manager $3$: Duration $5\mathrm{.}4$ years; Credit quality AA; Treasuries $40\%,$ Securitized

$($Mortgage$-$backed$)30\%,$ Corporates $30\%$ including a 'laddered' strategy with a given percent of the portfolio maturing each year to minimize trading costs.