Find the Limit of the Sequence $a _ { n } = \cos \left( \frac { n \pi } { 2 } \right)$

Multiple Choice

Find the limit of the sequence $a _ { n } = \cos \left( \frac { n \pi } { 2 } \right)$ .

A) 0
B) 1
C) $\frac { 3 \pi } { 2 }$
D) $- \frac { 3 \pi } { 2 }$
E) -1
F) $\frac { \pi } { 2 }$
G) $- \frac { \pi } { 2 }$
H) Divergent