The correct options are
A The commmon difference can be 3
B One of the term is −1
C Sum of the squares of the number is 21.
Let the numbers be
(a−d),a,(a+d)
Now,
(a−d)+a+(a+d)=−3⇒a=−1
Also,
(a−d)a(a+d)=8⇒a(a2−d2)=8⇒−1(1−d2)=8⇒d=±3
Therefore, the number are −4,−1,2 or 2,−1,−4
Sum of square =21