Find the Solution or Solutions, If Any Exist, to the System

Multiple Choice

Find the solution or solutions, if any exist, to the system.
- $$\left\{ \begin{array} { l } x + y + z = 7 \\x - y + 2 z = 7\end{array} \right.$$

A) infinitely many solutions of the form $x = 7 - \frac { 3 } { 2 } z , y = \frac { 1 } { 2 } z , z = z$
B) infinitely many solutions of the form $x = - 7 - \frac { 3 } { 2 } z , y = \frac { 1 } { 2 } z , z = z$
C) infinitely many solutions of the form $x = - 7 - \frac { 3 } { 2 } z , y = 2 z , z = z$
D) infinitely many solutions of the form $x = 7 - \frac { 3 } { 2 } z , y = 2 z , z = z$