Determine the First Step in Solving the System $\left\{ \begin{array} { l } 6 x + y - 6 z = - 3 \\8 x - 7 y - z = - 12 \\x - 5 y - 4 z = - 3\end{array} \right.$

Multiple Choice

Determine the first step in solving the system $\left\{ \begin{array} { l } 6 x + y - 6 z = - 3 \\8 x - 7 y - z = - 12 \\x - 5 y - 4 z = - 3\end{array} \right.$ by matrices.

A) Multiply row 1 by $- 6$ .
B) Interchange rows 1 and 3.
C) Interchange rows 1 and 2.
D) Multiply row 2 by $\frac { 1 } { 8 }$ .