In specific situations, it is possible to use un/une/des. Then, you are talking about what you want now rather than your general preferences.
-> Je préfère une pomme

I prefer an apple

-> je préfère des oranges
I'd rather have some oranges

Exceptions

When expressing your likes and dislikes, it is better to use le/la/l' /les

-> je préfère le jus d'orange
I prefer orange juice.
-> j'aime les oranges
I like oranges

Likes and dislikes

Talking about preferences

A taste in the negative takes le/la/l'/les as well

-> je n'aime pas les tartes.

I don't like pies/tarts

You can also like none! use ne ... ni...ni...

-> Je n'aime ni la tarte, ni le café!
I like neither the pie nor the coffee.

none

Use les + the number of options in your answer or use tous

-> j'aime les deux ! J'aime les trois !
I like both ! I like all three !

-> je les aime tous !
I like them all !

both / all

Other options

à vous !

Répondez selon l'illustration

Answer according to the picture

à l'écrit :)

Make sur to have a Capital letter at the beginning and a period at the end.