Actually we are dealing with a parabola

Using the distance formula

\(x= \dfrac{-b \pm \sqrt{b^2-4ac}}{2a}\)

\(x= \dfrac{-1 b \pm \sqrt{1^2-425*-5c}}{2*2}\)

\(x=-\frac{1}{4} \pm \dfrac{\sqrt{41}}{4}\)


The line of symmetry in the equation is namely -1/4

For quantity B the intercept is

\(x_1=-\frac{1}{4} + \dfrac{\sqrt{41}}{4}\)

\(x_2=-\frac{1}{4} - \dfrac{\sqrt{41}}{4}\)

Now the distance between the two points

\(|x_1-x_2|\)

\(|( \dfrac{-1}{4}+ \dfrac{\sqrt{41}}{4}) - (\dfrac{-1}{4}- \dfrac{\sqrt{41}}{4})|\)


\(| \dfrac{\sqrt{41}}{4}+ \dfrac{\sqrt{41}}{4}|=3.2\)

B is the answer