$42)$ A $25\mathrm{.}0-$g string is stretched with a tension of $43\mathrm{.}0$ N between two fixed points $12\mathrm{.}0$ m apart. What is

the frequency of the second harmonic? $42)\_\_\_\_\_\_$

A$)24\mathrm{.}0$ Hz B$)12\mathrm{.}0$ Hz C$)36\mathrm{.}0$ Hz D$)18\mathrm{.}0$ Hz E$)6\mathrm{.}00$ Hz