The capacitance formed between two concentric spherical metal shells having radii $x$ and $y$ with $y>x$ is
Note: $\epsilon$ is the permittivity of the medium between the shells.
- $4 \pi \epsilon\left(\dfrac{x y}{y-x}\right)$
- $4 \pi \epsilon\left(\dfrac{x^{2}}{y-x}\right)$
- $4 \pi \epsilon\left(\dfrac{y^{2}}{y-x}\right)$
- $4 \pi \epsilon\left(\dfrac{y^{2}-x y}{x}\right)$
