3. Let $z$ be a complex number, the argument of $z+2$ is $\frac{\pi}{3}$, and the argument of $z-2$ is $\frac{5 \pi}{6}$. Then $z$ equals ( ).
(A) $-\sqrt{3}+i$
(B) $-1+\sqrt{3} i$
(C) $-\frac{\sqrt{3}}{2}+\frac{1}{2} i$
(D) $-\frac{1}{2}+\frac{\sqrt{3}}{2} i$
3. (B).

Let $z=x+yi$, it is easy to know that $y>0$. According to the problem, we have $\left\{\begin{array}{l}\frac{y}{x+2}=\sqrt{3}, \\ \frac{y}{x-2}=-\frac{\sqrt{3}}{3} .\end{array}\right.$
By dividing the two equations, we get $x=\cdots \therefore y=\sqrt{3}$. Thus, $z=-1+\sqrt{3} i$.