Identify the Most Appropriate Test to Be Used to Determine $\sum _ { n = 1 } ^ { \infty } \frac { \cos n } { 6 ^ { n } }$

Multiple Choice

Identify the most appropriate test to be used to determine whether the series $\sum _ { n = 1 } ^ { \infty } \frac { \cos n } { 6 ^ { n } }$ converges or diverges.

A) Limit Comparison Test with $b _ { n } = \frac { 1 } { 6 ^ { n } }$
B) Direct Comparison Test with $b _ { \mathrm { n } } = \frac { 1 } { 6 ^ { n } }$
C) Alternating Series Test
D) Root Test
E) Ratio Test