A.2y2+z2=16 B.3y2+z2=16 C.2y2-z2=16 D.3y2-z2=16
A.2/3 B.1 C.2 D.3
A.x+y+z+2=0 B.x+y-z+2=0 C.x-y+z+2=0 D.x+y+z-2=0