If the line $x+y=2$ cuts the circle $x^2+y^2+2 x-4 y+4=0$ at two points A and B then the radius of the circle passing through $\mathrm{A}, \mathrm{B}$ and orthogonal to $x^2+y^2-2 x-4 y-4=0$ is

• A

  $3$
• B

  $4$
• Correct answer
  C

  $5$
• D

  $6$

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