Given Are the First Three Terms of a Sequence That $2 , \frac { 3 } { 2 } , 1$

Multiple Choice

Given are the first three terms of a sequence that is arithmetic. Find a1 and d.
- $2 , \frac { 3 } { 2 } , 1$

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