Answer: c) Al aire libre, sobre un fuego de leña
Explanation: The question says:
Traditionally, how is cooked the Paella?
Paella is a recipe from Spain, that has rice, seafood, and some vegetables as primary elements.
Usually, Paella is cooked in large quantities and is usually a dish prepared in family meetings and such.
It is usually cooked outside, over a wood fire.
Now, the option that says this is the option c:
"Al aire libre, sobre un fuego de leña"
That means:
"Outdoors, over a wood fire"