A.-1 B.1 C.2 D.3
A.x+2y-z-6=0 B.2x-y=0 C.y+2z=0 D.x+z=0
A.x-3y-2z=0 B.x+3y-2z-6=0 C.x-3y+2z+4=0 D.x+3y+2z-2=0