The verb prefer is followed by the preposition to when comparing two nouns or noun phrases.
Structure:
prefer + noun + to + noun
So:
I prefer regular classes to online classes.
Why the other options are incorrect?
❌ A) than – Prefer is not followed by than. Use to.
❌ B) by – Incorrect preposition after prefer.
❌ C) for – Incorrect preposition after prefer.
✅ D) to – Correct.
Examples