A straight wire carrying a current i₁ amperes runs along the axis of a circular coil carrying  current i₂ amperes. Then the force of interaction between the two current carrying conductors is

• A

  $\infty$

• B

  Zero

• C

  $\frac{{\mathrm{\mu }}_0}{4\mathrm{\pi }}\frac{2{\mathrm{i}}_1{\mathrm{i}}_2}{\mathrm{r}}\mathrm{N}/\mathrm{m}$

• D

  $\frac{2{\mathrm{i}}_1{\mathrm{i}}_2}{\mathrm{r}}\mathrm{N}/\mathrm{m}$