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The discriminant help us to identify the nature of the roots.

If Disc > 0, the function has two distinct roots
If Disc = 0, the function has repeated roots
If Disc < 0, the function has complex roots

The turning away of the function indicates a repeated root at that point.
Thus, the given quadratic equation has a repeated root at x = 2. So the discriminant of the function is zero.

Therefore, the correct answer is option B