Simplify the expression fully and state all domain exclusions: $\frac{y^2-4}{y^2+2y}$

$\frac{y-2}{y}$, where $y\ne 0$ and $y\ne -2$

$\frac{y-2}{y}$, where $y\ne 0$ only

$\frac{y+2}{y}$, where $y\ne -2$ only

$1$, for all real numbers $y$