apologies, I am new to here and trying my best to follow the way of posting but with a load of studying I forgot sometimes.
Now, my question is :
Did you think what are the maximum and minimum numbers that are there ?
May you please clarify how did you think of it ?

No worries,

In this type of QUES, GRE won't ask to answer how many numbers are there. There will be range of options and you need to pick up the correct one.

"May you please clarify how did you think of it ?"

I already mentioned above, for this type of Ques, you need to take the extreme side.

Think how you can make the value xy lowest?

and how yoou can make the value xy Highest?

Xmin = -8
Xmax = 2

Ymin = -4
Ymax = 10

You can form 4 cases of (XY);
(Xmin)(Ymin) = (-8)(-4) = 32
(Xmin)(Ymax) = (-8)(10) = -80
(Xmax)(Ymin) = (2)(-4) = -8
(Xmax)(Ymax) = (2)(10) = 20

Arrange them in ascending order: -80, -8, 20, 32

Thus, the Range = -80 ≤ XY ≤ 32