Find a General Term an for the Geometric Sequence $$a _ { 2 } = - 1 , \text { ag } = \frac { 1 } { 128 }$$

Multiple Choice

Find a general term an for the geometric sequence.
- $$a _ { 2 } = - 1 , \text { ag } = \frac { 1 } { 128 }$$

A) $a _ { n } = 2 \left( - \frac { 1 } { 2 } \right) ^ { n }$
B) $a _ { n } = \frac { 1 } { 2 } ( - 2 ) n - 1$
C) $a _ { n } = 6 \left( - \frac { 1 } { 4 } \right) ^ { n - 1 }$
D) $a _ { n } = 2 \left( \frac { 1 } { 2 } \right) ^ { n - 1 }$