A. ![-42](/tpl/images/0374/6784/d9f9d.png)
Step-by-step explanation:
We have been given a 2 by 2 matrix. We are asked to find the discriminant for our given matrix.
The discriminant for our given matrix would be product of negative 2 and 5 minus product of 4 and 8.
![\text{Discriminant}=-10-32](/tpl/images/0374/6784/2eb70.png)
![\text{Discriminant}=-42](/tpl/images/0374/6784/1752e.png)
Therefore, the discriminant for our given matrix is
and option A is the correct choice.