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

A

$$-\frac{5}{3}$$

B

$$\frac{3}{5}$$

C

$$\frac{-3}{10}$$

D

$$\frac{10}{3}$$