Obtain an Equivalent System by Performing the Stated Elementary Operation $x-2 y-7 z=17$

Obtain an equivalent system by performing the stated elementary operation on the system.
-Replace the third equation by the sum of itself and -1 times the second equation.
$x-2 y-7 z=17$
$-6 x+4 y+5 z=-9$
$8 x+7 y-z=-4$

A) $x-2 y-7 z=17$
$14 x+3 y-6 z=5$
$8 x+7 y-z=-4$
B) $x-2 y-7 z=17$
$-6 x+4 y+5 z=-9$
$14 x+3 y-6 z=5$
C) $x-2 y-7 z=17$
$-6 x+4 y+5 z=-9$
$2 x+11 y+4 z=-13$
D) $x-2 y-7 z=17$
$-6 x+4 y+5 z=-9$
$-14 x-3 y+6 z=5$