Recall the following:
• If the discriminant equals zero, the function has one real zero.
,
• If the discriminant is positive, the function has two real zeros.
,
• If the discriminant is negative, the function has two imaginary zeros.
Note that since the graph of the function intersects the x-axis at two points, the function has two real zeros.
Since there are two zeros, it follows that the discriminant must be positive.
The correct option is C.
