(a) $2\mathit{\mu }\mathrm{F}$ and $4\mathit{\mu }\mathrm{F}$ capacitors are to be connected in series. So, the effective capacitor will be

With , the $3\mathit{\mu }\mathrm{F}$ capacitor is to be connected in parallel. So, the equivalent capacitor will be

(b) Maximum value of capacitance may be obtained by connecting the capacitors in parallel. In that case, the equivalent capacitance will be, $\left(2+3+4\right)=$ $10\mathit{\mu }\mathrm{F}$.
Minimum value of capacitance may be obtained by connecting the capacitors in series. In that case, the equivalent capacitance will be ${\mathrm{C}}_{\mathrm{S}}$.
$\frac{1}{{\mathit{C}}_{\mathit{S}}}=\frac{1}{2}+\frac{1}{3}+\frac{1}{4}=\frac{13}{12}$
$\therefore {\mathit{C}}_{\mathit{S}}=\frac{12}{13}\mathit{\mu }\mathrm{F}$