The discriminant can be determined from the number of roots of the graph.
If Disc> 0, the function has two distinct roots
If Disc = 0, the function has a repeated root
If Disc < 0, the function has no real root.
Since the given graph has no real root, i.e. it does not cross x-axis at any point, so we can say that the discriminant of the given function is negative.
So the answer to this question is option C