Which of the Following Series Can Be Shown to Be $\sum _ { n = 1 } ^ { \infty } \frac { 1 } { n ^ { 2 } }$

Multiple Choice

Which of the following series can be shown to be convergent using the Ratio Test?
1) $\sum _ { n = 1 } ^ { \infty } \frac { 1 } { n ^ { 2 } }$
2) $\sum _ { n = 1 } ^ { \infty } \frac { n } { 3 ^ { n } }$
3) $\sum _ { n = 1 } ^ { \infty } \frac { 2 ^ { n } } { n ! }$

A) None
B) 1
C) 2
D) 3
E) 1, 2
F) 1, 3
G) 2, 3
H) 1, 2, 3