The axis of symmetry for $f(x)=2x^2-7x+20$ is

Question

$\begin{array}{1 1} (a)\; \large\frac{7}{2} \\ (b)\;\large\frac{-7}{2} \\ (c)\;\large\frac{2}{7}\\(d)\;\large\frac{-2}{7}\end{array}$