Solve the System $$\begin{array} { c } x + y + z = - 4 \\x - y + 4 z = 21 \\2 x + y + z = - 8\end{array}$$

Multiple Choice

Solve the system.
- $$\begin{array} { c } x + y + z = - 4 \\x - y + 4 z = 21 \\2 x + y + z = - 8\end{array}$$

A) $\{ ( 5 , - 4 , - 5 ) \}$
B) $\{ ( 5 , - 5 , - 4 ) \}$
C) $\{ ( - 4 , - 5,5 ) \}$
D) $\varnothing$