A parallel-plate capacitor has plates of area $0.01\ \text{m}^2$, $2\ \text{mm}$ apart. A slab of dielectric constant $4$ and thickness $1\ \text{mm}$, as large as the plates, is placed between them. Take $\varepsilon_0 = 8.85 \times 10^{-12}\ \text{F/m}$. The capacitance is closest to