For what values of $k$ does the equation $x^2+5kx+16=0$ has no real roots.

Question

$\begin{array}{1 1}(A) \; \large\frac{-8}{5}\normalsize > k >\large\frac{8}{5}\\(B)\;\large\frac{-8}{5}\normalsize < k <\large\frac{8}{5}\\(C)\;\large\frac{-8}{5}\normalsize \geq k \geq\large\frac{8}{5} \\(D)\;\large\frac{-8}{5}\normalsize \leq k \leq\large\frac{8}{5}\end{array}$</span>