Correct option is c $E \neq 0$ if $\phi$ is changing.
Farady’s law states that time varying magnetic flux can induce an e.m.f. $\mathrm{E}=$ Electric field, Induced
$$
\mathrm{E}=-\frac{\mathrm{d} \phi}{\mathrm{dt}}
$$
$$
\begin{array}{l}
\mathrm{E}=-\frac{\mathrm{d} \phi}{\mathrm{dt}} \\
\mathrm{E}=0 \text { only if } \frac{\mathrm{d} \phi}{\mathrm{dt}}=0
\end{array}
$$
If $\mathrm{E}=0$, then $\phi=$ const.
$\mathrm{E} \neq 0$, then $\phi$ is changing