Find the Fifth Term and the Nth Term of the Geometric

Multiple Choice

Find the fifth term and the nth term of the geometric sequence whose initial term, a, and common ratio, r, are given.
- $$a = 1 ; r = \frac { 1 } { 2 }$$

A) $a _ { 5 } = \frac { 1 } { 16 } ; a _ { n } = 1 \cdot \left( \frac { 1 } { 2 } \right) ^ { n - 1 }$
B) $a _ { 5 } = \frac { 1 } { 32 } ; a _ { n } = 1 \cdot \left( \frac { 1 } { 2 } \right) ^ { n - 1 }$
C) $a _ { 5 } = \frac { 1 } { 32 } ; a _ { n } = 1 \cdot \left( \frac { 1 } { 2 } \right) ^ { n }$
D) $a _ { 5 } = \frac { 1 } { 16 } ; a _ { n } = 1 \cdot \left( \frac { 1 } { 2 } \right) ^ { n }$