1 In the complex plane, the point corresponding to the complex number $z$ moves on the bisector of the $\mathrm{I}$ and III quadrants. Then, the trajectory of the point corresponding to $z^{2}$ is
A. Line
B. Ray
C. Parabola
D. Circle
1 B. According to the problem, $z=a+a i(a \in \mathbf{R})$. Therefore, $z^{2}=2 a^{2} i$. It is clear that the real part of the complex number $z^{2}$ is zero, and the imaginary part is a non-negative real number.