Find the Sum of the Infinite Geometric Series $\sum _ { n = 1 } ^ { \infty } 3 \left( \frac { 1 } { 2 } \right) ^ { n - 1 }$

Multiple Choice

Find the sum of the infinite geometric series. $\sum _ { n = 1 } ^ { \infty } 3 \left( \frac { 1 } { 2 } \right) ^ { n - 1 }$

A) $6$
B) $3$
C) $12$
D) $9$
E) $18$