Find the Radius of Convergence and the Interval of Convergence $$\sum _ { n = 1 } ^ { \infty } \frac { ( - 1 ) ^ { n } ( x - 8 ) ^ { n } } { \sqrt { n } }$$

Multiple Choice

Find the radius of convergence and the interval of convergence of the power series.
$$\sum _ { n = 1 } ^ { \infty } \frac { ( - 1 ) ^ { n } ( x - 8 ) ^ { n } } { \sqrt { n } }$$

A) $R = 1 , l = [ 7,9 )$
B) $R = 1 , I = ( 7,9 ]$
C) $R = 8 , l = [ - 8,8 )$
D) $R = 8 , I = ( - 8,8 )$