# The coefficient of the middle term in the binomial expansion in powers of $(1 + \alpha x)^4$ and of $(1- \alpha x)^6$ is the same if $\alpha$ equals
( A ) $\frac{3}{5}$
( B ) $\frac{10}{3}$
( C ) $-\frac{5}{3}$
( D ) $\frac{-3}{10}$