Let $A = \left[ \begin{array} { c c } i & - i \\ - i & i \end{array} \right] , i = \sqrt { - 1 }$. Then, the system of linear equations $A ^ { 8 } \left[ \begin{array} { l } x \\ y \end{array} \right] = \left[ \begin{array} { c } 8 \\ 64 \end{array} \right]$ has :\\
(1) A unique solution\\
(2) Infinitely many solutions\\
(3) No solution\\
(4) Exactly two solutions