Which of the Following Systems of Equations Has as a Solution

Multiple Choice

Which of the following systems of equations has as a solution the ordered triple $( 3,1,2 )$ System I: $$\left\{ \begin{array} { c } 3 x + 5 y - 3 z = 7 \\- 5 x + 6 y - 5 z = - 15 \\- 6 x - 2 y - 6 z = - 36\end{array} \right.$$ System II: $$\left\{ \begin{array} { l } 5 x - 5 y - 3 z = 4 \\- 5 x - 2 y + z = - 15 \\6 x + y - 5 z = 9\end{array} \right.$$ System III: $$\left\{ \begin{array} { r } 6 x - 3 y + 2 z = 19 \\3 x + y - 6 z = - 2 \\5 x + 4 y - 2 z = 15\end{array} \right.$$

A) Only system III has the ordered triple $( 3,1,2 )$ as a solution.
B) Only systems II and III have the ordered triple $( 3,1,2 )$ as a solution.
C) Only systems I and II have the ordered triple $( 3,1,2 )$ as a solution.
D) Each of the systems I, II, and III has the ordered triple $( 3,1,2 )$ as a solution.
E) Only system I has the ordered triple $( 3,1,2 )$ as a solution.