Find a Formula for the General Term $a _ { n }$

Multiple Choice

Find a formula for the general term $a _ { n }$ of the sequence $\left\{ - \frac { 1 } { 2 } , 0 , \frac { 1 } { 10 } , \frac { 2 } { 17 } , \frac { 3 } { 26 } , \ldots \right\}$ .

A) $\frac { ( n - 2 ) } { \left( n ^ { 2 } + 1 \right) }$
B) $\frac { ( n - 2 ) } { \left( n ^ { 2 } - 1 \right) }$
C) $\frac { ( n + 2 ) } { \left( n ^ { 2 } + 1 \right) }$
D) $\frac { ( - 1 ) ^ { n } ( n - 2 ) } { \left( n ^ { 2 } + 1 \right) }$
E) $\frac { ( n - 2 ) } { n ^ { 2 } }$
F) $\frac { n } { \left( n ^ { 2 } + 1 \right) }$
G) $\frac { ( n - 1 ) } { \left( n ^ { 2 } + 1 \right) }$
H) None of these