The correct answer to your question is option B. "Cuàles."
The question is asking "What are your favorite fruits?". "Fruits" is a plural noun so the correct answer is cuàles. If the question was asking "What is your favorite fruit?", then your answer would be option A since it is a singular noun.
</span>Cuáles" is for plural words whereas Cuál refers to singular objects/words. This essentially means that because of the usage of the word, "<span>frutas," which is plural, then B would be the correct answer.</span>
1. Ana ve la televisión y bebe café 4. Marcos y Juan leen 5. Yo vivo en Madrid 6. Mis amigos y yo recibimos un premio 7. Luis y Raúl escriben en el cuaderno 8. El niño aprende español 9. Yo duermo en la cama 10. Jose abre la caja