d
\(\varepsilon=-\frac{\mathrm{d} \phi}{\mathrm{dt}}=\frac{-\mathrm{d}}{\mathrm{dt}}\left(\mu_{0} \mathrm{nl}\right)\left(\pi \mathrm{R}^{2}\right) \)

\(=-\left(\mu_{0} \mathrm{n} \pi \mathrm{R}^{2}\right) \frac{\mathrm{d} l}{\mathrm{dt}} \)

\(=-\mu_{0} \mathrm{n} \pi \mathrm{R}^{2} \frac{\mathrm{d}\left(\mathrm{kt} \mathrm{e}^{-\mathrm{at}}\right)}{\mathrm{dt}} \)

\(=-\mathrm{C}\left(\mathrm{t}\left(e^{-a t}\right)(-\alpha)+\mathrm{e}^{-a t}\right) \quad(\mathrm{C} \rightarrow \mathrm{constant}) \)

\(=-\mathrm{C}\left(\mathrm{e}^{-a t}\right)(1-\alpha \mathrm{t})\)

Clearly, at \(t=0\) 

Induced current \(\neq 0\) 

Also, apply Lenz law to find correct option.