How much length of a very thin wire is required to obtain a solenoid of length  l₀ and inductance L

• A

  $\sqrt{\frac{2{\mathrm{\pi Ll}}_0}{{\mathrm{\mu }}_0}}$

• B

  $\sqrt{\frac{4{\mathrm{\pi Ll}}_0}{{\mathrm{\mu }}_0^2}}$

• C

  $\sqrt{\frac{4{\mathrm{\pi Ll}}_0}{{\mathrm{\mu }}_0}}$

• D

  $\sqrt{\frac{8{\mathrm{\pi Ll}}_0}{{\mathrm{\mu }}_0}}$