Determine the Interval of Absolute Convergence for the Given Power $\sum _ { k = 0 } ^ { \infty } k ^ { 2 } \left( \frac { x } { 6 } \right) ^ { k }$

Determine the interval of absolute convergence for the given power series. $\sum _ { k = 0 } ^ { \infty } k ^ { 2 } \left( \frac { x } { 6 } \right) ^ { k }$

A) $- 6 < x < 6$
B) All real x
C) $- 1 < x < 1$
D) $- \frac { 1 } { 6 } < x < \frac { 1 } { 6 }$