Est-ce que tu préfères le boeuf, le poulet, ou le poisson? What if I prefer neither one of these. How Would I answer that in French?

Est-ce que tu préfères le ketchup ou la moutarde avec les hamburgers?
I prefer neither one. Again, how would I say that in French?

2 answers

You do not have to like any of them to prefer one. Which do you dislike least? Are you making a point that you are vegetarian? If so, say so.
Je ne préfère ni (whatever you'd like to name first) ni (whatever you'd like to name second.

Sra (aka Mme)