a
\(\mathrm{C}_{\mathrm{eq}}=0.5\, \mu \mathrm{F}=\frac{\left(1+\frac{4}{3}\right) \mathrm{C}}{\frac{7}{3}+\mathrm{C}}=\frac{7 \mathrm{C}}{\frac{7}{3}+\mathrm{C}}=\frac{1}{2}\)
\(\Rightarrow \quad \frac{14 \mathrm{C}}{3}=\mathrm{C}+\frac{7}{3}\)
\(C=\frac{7}{11}\)