Find the Radius of Convergence of the Series $\sum _ { n = 1 } ^ { \infty } \frac { n ^ { n } ( x + 1 ) ^ { n } } { 3 ^ { n } }$

Multiple Choice

Find the radius of convergence of the series $\sum _ { n = 1 } ^ { \infty } \frac { n ^ { n } ( x + 1 ) ^ { n } } { 3 ^ { n } }$ .

A) 0
B) 2
C) 3
D) 4
E) $\frac { 1 } { 2 }$
F) 1
G) 5
H) $\infty$