Which sentence(s) do you deem correct referring to categories in general?
(GENERALIZATION)
I understand that both ‘pear’ and ‘apple’ are count nouns.
(A) I prefer apple to pear.
(B) I prefer an apple to a pear.
© I prefer apples to pears.
Thx
This is the only natural choice: © I prefer apples to pears.
Thank you again.
What do you think about the following sentence pairs?
(1) A tiger is a dangerous predator.
(2) Tigers are dangerous predators.
They are coursebook examples, I’ll inform you of the right answer afterwards. 
Both sound natural enough to me. I can think of a number of contexts for each.
Do I detect a hint of sarcasm or scepticism about your mention of ‘the correct answer’, Kogyuri? 
Well done it Beeesneees!
Both are correct grammatically, according to the course book.
This is why I don’t quite understand why “I prefer appleS to pearS” is
the only right answer in the above-mentioned (thread-initial) sentence pair.
What do you think about “I prefer AN apple to A pear.”?
I think both are correct grammatically. Which one would you use more often?
Certain fruits (kinds of fruit), like ‘grapes’, are non-count, but as far as I know
neither ‘plum’ nor ‘melon’ are. I’m getting confused … 
Your second set of examples (tigers) aren’t like the first set (fruit) though!
If you had offered me these choices:
A)I prefer a tiger to a lion.
B) I prefer tigers to lions.
then I would have said (B) is more natural.
With regard to the original question, I don’t know if this will help, or just confuse matters more, but:
The natural choice in the original options is © as Mister Micawber has pointed out.
Note that he didn’t say it was the only choice. There are specific contexts where (B) is correct, however, the key point is that your original question indicated you wanted to know in general terms.
When generalising or in usually usage, if you were simply stating your preference, you would say,
‘I prefer apples to pears.’
In answer to specific questions or in specific contexts you might use,
‘I prefer an apple to a pear’.
I see, thank you. So, summing up your answers in a context:
(There are pears and apples on the table before me.)
Friend: Which one would you like?
ME: I’d like AN apple. / I’d prefer AN apple.
(I will take an apple now if you don’t mind. CHOICE And I also add …)
I prefer appleS to pearS after all.
(I like apples more than pears in general. GENERALIZATION)
Is this what you are suggesting Beeesneees?
That’s correct, but just to add the phrase you originally queried:
(There are pears and apples on the table before me.)
Friend: Which one would you like?
ME: Usually I’d prefer the taste of a pear to an apple, but those apples look so appealing, that I would like an apple.
Or rather:
…
ME: Usually I’d prefer the taste of pearS to appleS {{GENERALLY SPEAKING about the 2
sorts of fruit >>> the PLURALIZATION of these COUNT NOUNS is “more natural”
here according to You and Mister Micawber, or not? :)}}, but those (SPECIFIED) apples
look so appealing, that I’d like an apple (CHOICE).
???