a b c d

d

$\text{Current passing through inductor is I } = \frac{E}{R_2} (1 - e^{\frac{-tR_2}{L}})$ $ \frac{dI}{dt} = \frac{E}{L} (1 - e^{\frac{-tR_2}{L}})$ $ V_L = L\frac{dI}{dt} = E (1 - e^{\frac{-tR_2}{L}}) = 12 e^{-5t}$