A conducting rod of length L is falling with velocity v perpendicular to a uniform horizontal magnetic field B; the potential difference between its two ends will be :

• A

  2BLv

• B

  BvL

• C

  $\frac{1}{2}\mathrm{BvL}$

• D

  ${\mathrm{B}}^2{\mathrm{v}}^2{\mathrm{L}}^2$