Find the Curvature of the Space Curve $\kappa = - \frac { 1 } { 3 t }$

Multiple Choice

Find the curvature of the space curve.
-r(t) = (3 t sin t + 3 cos t) i + 3j + (3t cos t - 3 sin t) k

A) $\kappa = - \frac { 1 } { 3 t }$
B) $\kappa = \frac { 1 } { 9 t ^ { 2 } }$
C) $\kappa = 3 t$
D) $\kappa = \frac { 1 } { 3 t }$