Determine the Radius of Convergence for the Given Power Series $\sum _ { k = 0 } ^ { \infty } \frac { 7 ^ { k - 1 } x ^ { k } } { k }$

Multiple Choice

Determine the radius of convergence for the given power series. $\sum _ { k = 0 } ^ { \infty } \frac { 7 ^ { k - 1 } x ^ { k } } { k }$

A) $R =$ 7
B) $R =$ $\infty$
C) $R =$ $\frac { 1 } { 7 }$
D) $R =$ 0