mm$-$diameter segment $(1)$ and a solid $60-$mm$-$diameter segment $(2).$ The allowable shear stress of the steel is $96$ MPa $,$ and the maximum rotation angle at the free end of the compound shaft must be limited to $C4.$ Determine the magnitude of the largest torque TC that may be applied at $C.$

$4\mathrm{.}11kN-m$

$4\mathrm{.}46kN-m$

$3\mathrm{.}52kN-m$

$14\mathrm{.}68kN-m$