18. the integral surface satisfying the partial difterential equation ion+2 0 and passing through the straight line x x=1, y =z is (a) (x- 1)z + ? = y2 (c)y- 2)

18. The integral surface satisfying the partial difterential equation ion+2 0 and passing through the straight line x x=1, y =z is (A) (x- 1)z + ? = y2 (C)y- 2)x + x*= 1 (B) x+y-=1 (D) x- 1) z*z"y