A coil having an area A₀ is placed in a magnetic field which changes from B₀ to 4B₀ in a time interval t. The e.m.f. induced in the coil will be

• A

  $\frac{3{\mathrm{A}}_0{\mathrm{B}}_0}{\mathrm{t}}$

• B

  $\frac{4{\mathrm{A}}_0{\mathrm{B}}_0}{\mathrm{t}}$

• C

  $\frac{3{\mathrm{B}}_0}{{\mathrm{A}}_0\mathrm{t}}$

• D

  $\frac{4{\mathrm{B}}_0}{{\mathrm{A}}_0\mathrm{t}}$