If the system of equations $2 x + 3 y - z = 0 , x + k y - 2 z = 0$ and $2 x - y + z = 0$ has a non-trivial solution $( x , y , z )$, then $\frac { x } { y } + \frac { y } { z } + \frac { z } { x } + k$ is equal to\\
(1) $- \frac { 1 } { 4 }$\\
(2) $\frac { 1 } { 2 }$\\
(3) $- 4$\\
(4) $\frac { 3 } { 4 }$