Find $a _ { 1 }$ And and R for a Geometric Sequence

Multiple Choice

Find $a _ { 1 }$ and and r for a geometric sequence { $\left\{ a _ { n } \right\}$ } from the given information.
- $a _ { 2 } = 18$ and $a _ { 7 } = 4,374$

A) $a _ { 1 } = 18$ and $r = 3$
B) $a _ { 1 } = 6$ and $r = 3$
C) $a _ { 1 } = 6$ and $r = 12$
D) $a _ { 1 } = 18$ and $r = 12$