Question

3. Correct the sentences : (a) I prefer tea than coffee.

Answer 1

I prefer tea to coffee.

Answer 2

The sentence : I  prefer tea than coffee is incorrect.

When we have to compare two actions or things, we always use preposition "to".

So "prefer to" phrase is used rather than "prefer than."  

So, preposition "than" is wrong  and we must use preposition "to."

Therefore, the correct sentence is: I prefer tea to coffee.

While comparing we use "rather than."