For which discriminant is the graph possible? a. b^2 - 4ac = -12b. b^2 - 4ac = 0c. b^2 - 4ac = 7

The discriminant tells us how many real solutions there are. Since the parabola doesn't have any x-intercepts, the discriminant is less than zero, and therefore is answer A.

If a discriminant is:
>0, there are 2 x-intercepts
=0, there is 1 x-intercept
<0, there are no x-intercepts