Given Are the First Three Terms of a Sequence That $- 14 , - 17 , - 20$

Multiple Choice

Given are the first three terms of a sequence that is arithmetic. Find a1 and d.
- $- 14 , - 17 , - 20$

A) $\mathrm { a } _ { 1 } = - 14 ; \mathrm { d } = 9$
B) $\mathrm { a } _ { 1 } = - 14 ; \mathrm { d } = - 6$
C) $a _ { 1 } = - 14 ; d = - 3$
D) $\mathrm { a } _ { 1 } = - 14 ; \mathrm { d } = - 9$