Which statement correctly interprets the value of the discriminant $D=b^2-4ac$ for a quadratic equation $a{x}^2+bx+c=0$?

If $D>0$, the equation has two identical real roots and the vertex is on the $x$-axis

If , the equation has two complex solutions and the graph does not cross the $x$-axis

If $D=0$, the equation has no real solutions and the graph is entirely above or below the $x$-axis

If $D>0$, the equation has no real solutions because the discriminant must be negative for real roots