The correct option is C b2≥−4c
For an equation ax2+bx+c=0 to have real roots, the discriminant (D) must be greater than or equal to zero.
i.e., D≥0, where D=b2−4ac
⇒b2−4ac≥0, when the roots are real.
With respect to the given equation, b2−4ac=b2+4c.
∴ For the roots of the equation to be real, we must have b2+4c≥0⟹b2≥−4c.