The coefficients of the middle terms in the binomial expansion in powers of x of $(1+\alpha x)^4$ and of $(1- \alpha x )^6$ are the same if $\alpha$ equals

Question

$\begin{array}{1 1}(A)\;\frac{-5}{3} \\(B)\;\frac{3}{5} \\(C)\;\frac{-3}{10} \\ (D)\;\frac{10}{3} \end{array}$