A $4\mathrm{.}2-$kg mass is placed at $(3\mathrm{.}0,4\mathrm{.}0)$ m$.$ Where can an $8\mathrm{.}4-$kg mass be placed so that the moment of inertia about the z$-$axis is zero? a$.(3\mathrm{.}0,4\mathrm{.}0)$ m b$.(6\mathrm{.}0,8\mathrm{.}0)$ m c$.(1\mathrm{.}5,2\mathrm{.}0)$ m d$.$ There is no position giving this result.