Write a Formula for the Nth Term of the Geometric $8,4,2,1 , \ldots$

Multiple Choice

Write a formula for the nth term of the geometric sequence.
- $8,4,2,1 , \ldots$

A) $a _ { n } = 8 \left( \frac { 1 } { 2 } \right) ^ { n + 1 }$
B) $a _ { n } = 8 \left( \frac { 1 } { 2 } \right) ^ { n }$
C) $a _ { n } = 8 \left( \frac { 1 } { 2 } \right) ^ { n - 1 }$
D) $a _ { n } = 8 - \left( \frac { 1 } { 2 } \right) ^ { n - 1 }$