Given Are the First Three Terms of a Sequence That $2,6,18 , \ldots$

Multiple Choice

Given are the first three terms of a sequence that is either arithmetic or geometric. If the sequence is arithmetic, find a1
and d. If a sequence is geometric, find a1 and r.
- $2,6,18 , \ldots$

A) $a _ { 1 } = 2 , r = \frac { 1 } { 3 }$
B) $a _ { 1 } = 2 , r = - 3$
C) $a _ { 1 } = 2 , r = 3$
D) $a _ { 1 } = 2 , d = 3$