Correct option is : (1) \(\frac{11 \varepsilon_{0} \mathrm{A}}{18 \mathrm{d}}\)
All capacitor are in parallel combination.
Also effective area is common area only
\(\Rightarrow \mathrm{C}_{\mathrm{eq}}=\mathrm{C}_{1}+\mathrm{C}_{2}+\mathrm{C}_{3}\)
\(\Rightarrow \mathrm{C}_{\mathrm{eq}}=\frac{\mathrm{A} \varepsilon_{0}}{3 \mathrm{d}}+\frac{\mathrm{A} \varepsilon_{0}}{3(2 \mathrm{d})}+\frac{\mathrm{A} \varepsilon_{0}}{3(3 \mathrm{d})}\)
\(\Rightarrow \mathrm{C}_{\text {eq }}=\frac{\mathrm{A} \varepsilon_{0}}{3}\left(\frac{11}{6 \mathrm{d}}\right)\)
\(\Rightarrow \mathrm{C}_{\mathrm{eq}}=\frac{11 \mathrm{A} \varepsilon_{0}}{18 \mathrm{d}}\)