La or las?
 

QA: A mí me apetecen las tortillas y la paella.
QB: A mí también, pero ___ prefiero de otro sabor.
A: 1) lo 2) la 3) los 4) las
Is it possible to have here la instead of las (if you're referring to just paella?)

Yes.

I agree, but you would have to make clear you are only talking about paella.

Thanks all for your replies. But in this specific case, the article singular/plural is enough to differentiate which one you're referring to or you still need to be more specific (by mentioning the name/noun)? So when I reply using la, I'm referring to paella, if I reply using las, I'm referring to either paella+tortillas or just tortillas.

If someone is talking to you about two items, but your answer refers to only one, you must make clear what you are talking about or your listener will be disconcerted.

"Las" replaces both items, not only one, so:
If you want to talk about paella: "A mí también, pero prefiero la paella de otro sabor".
If you are talking about tortillas: "A mí también, pero prefiero las tortillas de otro sabor."

Muchas gracias.