d
Consider the Gaussian surface where the induced charge is as shown in the figure
The net field at $\mathrm{P}$ due to the charges is zero,
i.e.,
$-2 Q+\frac{q}{2 A \varepsilon_{0}}(l e f t)+\frac{q}{2 A \varepsilon_{0}}(r i g h t)+q-\frac{q}{2 A \varepsilon_{0}}(r i g h t)=0$
$\Rightarrow-2 q+1-Q+q=0$
$\Rightarrow q=\frac{3}{2} Q$
Charge on the right side of the rightmost plate is
$-2 Q+Q=-2 Q+\frac{3}{2} Q=-\frac{Q}{2} c$