The discriminant determines the nature of the roots of a quadratic equation. The word 'nature' refers to the types of numbers the roots can be — namely real, rational, irrational or imaginary. ... If Δ≥0, the expression under the square root is non-negative and therefore roots are real.
The correct answer is D because there is one area that is a cluster (bundle of dots in one area) and one outlier (away from all the other points; irrelevant).
