Use Back-Substitution to Solve the System of Linear Equations $$\left\{ \begin{array} { c c c } - 3 x - 9 y - 7 z & = 0 \\4 y + 2 z & = - 8 \\z & = & 6\end{array} \right.$$

Multiple Choice

Use back-substitution to solve the system of linear equations. $$\left\{ \begin{array} { c c c } - 3 x - 9 y - 7 z & = 0 \\4 y + 2 z & = - 8 \\z & = & 6\end{array} \right.$$

A) $( 1,6 , - 5 )$
B) $( - 5,1,6 )$
C) $( 3 , - 5,6 )$
D) $( 1 , - 5,6 )$
E) $( 6 , - 5,1 )$