3. Given $z_{1}, z_{2}$ are two given complex numbers, and $z_{1} \neq z_{2}$, they correspond to points $Z_{1}$ and $Z_{2}$ on the complex plane, respectively. If $z$ satisfies $\left|z-z_{1}\right|-\left|z-z_{2}\right|=0$, then the set of points $Z$ corresponding to $z$ is
A. Hyperbola
B. The perpendicular bisector of the line segment $Z_{1} Z_{2}$
C. Two intersecting lines passing through $Z_{1}$ and $Z_{2}$, respectively
D. Ellipse
3. B $\left|z-z_{1}\right|=\left|z-z_{2}\right|$, the set of points $Z$ is the perpendicular bisector of the line segment $Z_{1} Z_{2}$