已知 t = linspace(0,20*pi, 501); plot3(t.*sin(t), t.*cos(t), t); 命令执行后绘制出上图, 如要绘制下图可以使用的命令是( )。 A. plot3(t.*sin(t),t.*cos(t),t); hold on plot3(t.*sin(t), t.*cos(t), -t); B. plot3(t.*sin(t),t.*cos(t),t,t.*sin(t),t.*cos(t),-t); C. plot3(t.*sin(t),t.*cos(t),[t;-t]); D. plot3(t.*sin(t),t.*cos(t),[t,-t]);