Answer: La tortilla.
Explanation: An omelet on a white plate with a green leaf-based garnish (usually bay leaf)
The given options are:
El sancocho: is a type of soup, so this is far away from an omelet.
La tortilla: is a type of preparation that uses eggs as a binding ingredient, this not "exactly" an omelet, but is close enough.
Los asados: This is a way of preparing meat, so this is not an omelet.
Croquetas: this is a way of preparing different things, where you coat something with breadcrumbs and you fry it, this is not an omelet.
So the only option that matches is "La tortilla"