Capacitance ' $\text{C}$ ' of a parallel plate structure is calculated as $20 ~ \mathrm{pF}$ using $C=\frac{\varepsilon_0 \varepsilon_r A}{d}$, where $\varepsilon_o$ is the permittivity of free space, $\varepsilon_r$ is the relative permittivity of the dielectric, $A$ is the overlapping area of the electrodes and $d$ is the distance between them. The value of $C$ is then measured using an LCR meter. If the meter is assumed to be ideal and it introduces no error due to cable capacitance, which one of the following readings is likely to be correct?
- $20.5 ~ \mathrm{pF}$
- $20 ~ \mathrm{pF}$
- $19.5~ \mathrm{pF}$
- $10 ~ \mathrm{pF}$