Line $L_1\equiv 3x-4y+1=0$ touches the circles $C_1$ and $C_2.$ Centres of $C_1$ and $C_2$ are $A_1\left(\mathrm{1,2}\right)$ and $A_2\left(\mathrm{3,1}\right)$ respectively, then identify the INCORRECT statement from the following statements.

• Correct answer
  A

  $L_1$ is direct common tangent of these circles
• B

  $L_1$ is transverse common tangent to these circles
• C

  Radius of circle $C_1$ is $\frac{4}{5}$ units
• D

  Radius of circle $C_2$ is $\frac{6}{5}$ units

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