$\begin{array}{1 1} (a)\;\bigg(\large\frac{\alpha+\beta}{2},f\frac{(\alpha +\beta)}{2}\bigg) \\ (b)\;\bigg(\large\frac{\alpha- \beta}{2},f\frac{(\alpha -\beta)}{2}\bigg) \\ (c)\;\bigg(\large\frac{-\alpha+\beta}{2},f\frac{(\alpha +\beta)}{2}\bigg) \\(d)\;\text{ none of the above} \end{array} $
