Write a Formula for the General Term (The Nth Term) $$3 , - 1 , \frac { 1 } { 3 } , - \frac { 1 } { 9 } , \frac { 1 } { 27 } , \ldots$$

Multiple Choice

Write a formula for the general term (the nth term) of the geometric sequence.
- $$3 , - 1 , \frac { 1 } { 3 } , - \frac { 1 } { 9 } , \frac { 1 } { 27 } , \ldots$$

A) $a _ { n } = 3 \left( - \frac { 1 } { 3 } \right) ^ { n }$
B) $a _ { n } = 3 \left( - \frac { 1 } { 3 } \right) ^ { n + 1 }$
C) $a _ { n } = 3 \left( - \frac { 1 } { 9 } \right) ^ { n - 1 }$
D) $a _ { n } = 3 \left( - \frac { 1 } { 3 } \right) ^ { n - 1 }$