If the equation of the plane passing through the points $(2,1,2),(1,2,1)$ and perpendicular to the plane $2 x-y+2 z=1$ is $a x+b y+c z+d=0$ then $\frac{a+b}{c+d}=$

• A

  $0$
• B

  $1$
• Correct answer
  C

  $-1$
• D

  $2$

Hence, the correct answer is option: 'C'.