If the eight vertices of a regular octagon are given by the complex numbers $\frac{1}{x_{\mathrm{j}}-2 i}(\mathrm{j}=1,2,3,4,5,6,7,8)$, then the radius of the circumcircle of the octagon is

• Correct answer
  A

  $\frac{1}{4}$
• B

  $\frac{1}{4}i$
• C

  i
• D

  2

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