Which quadratic graph below has a negative discriminant?

The graph in (A)

Step-by-step explanation:

Negative discriminant of a quadratic function implies the corresponding quadratic equation ax^2+bx+c=0 does not have any real solutions (it still has solutions in the complex domain, however). Graphically, this corresponds to a parabola that never intersects the x axis for any value x, i.e. it lies either fully above or fully below the x axis. This situation is depicted in the case (A), where the parabola lies below the x axis and has no x-intercepts.

The cases (B), (C), and (D) all intersect the x axis in at least one point.

x is the total time in minutes for the free response

you are given number of questions as 15 - m and time per item as 8 minutes

to find x multiply the two givens together:

x = 8 * (15-m) = 8(15-m)