An Augmented Matrix That Represents a System of Linear Equations $x , y$

Multiple Choice

An augmented matrix that represents a system of linear equations (in variables $x , y$ , and $z$ ) has been reduced using Gauss-Jordan elimination. Write the solution represented by the augmented matrix.
$$\left[ \begin{array} { c c c : c } 1 & 0 & 0 & 9 \\0 & 1 & 0 & 8 \\0 & 0 & 1 & - 7\end{array} \right]$$

A) $x = 9 , y = 8 , z = - 7$
B) $x = - 9 , y = - 8 , z = 7$
C) $x = 0 , y = 0 , z = 0$
D) $x = 9 x , y = - 7 y , z = 8 z$
E) $x = 9 , y = 0 , z = 0$