Five plates are arranged as shown in the figure and connected across a battery of emf V. The separation between each plate is d and surface area of each plate is A.

$\mathrm{C}=\frac{{\mathrm{A\epsilon }}_0}{\mathrm{d}}\frac{1}{{\mathrm{C}}_{\mathrm{eq}}}=\frac{1}{\mathrm{C}}+\frac{2}{3\mathrm{C}}=\frac{5}{3\mathrm{C}}$    Option (B) is correct. Option (A) is wrong.

Total charge, $Q={\left(C_{eq}\right)}_{PQ}V=\frac{3A{\epsilon }_{0}V}{5d}$
In parallel combination, charge is proportional to capacitance.
Charge on plate 1, $\frac{C/2}{3C/2}\times Q=\frac{Q}{3}=\frac{1}{3}\frac{3A{\epsilon }_{0}V}{5d}=\frac{A{\epsilon }_{0}V}{5d}$   

Option (C) is correct.
Charge on plate 3 in lower branch $=\frac{A{\epsilon }_{0}V}{5d}$
Charge on plate 3 in upper branch $=Q-\frac{A{\epsilon }_{0}V}{5d}=\frac{2A{\epsilon }_{0}V}{5d}$
Total charge on plate 3 $=Q=\frac{3A{\epsilon }_{0}V}{5d}$  Option (D) is correct.