6.B ¿Qué? or ¿Cuál?
As we have seen in the past, there are many interrogative words, but two of them that always cause questions on when to use them. ¿qué? and ¿cuál? or ¿cuáles? mean what? or which? However, they are not interchangeable.
¿Qué? Is used to ask about a definition or an explanation.
¿Qué es una flor? What is a flower?
¿Cuál? Is used to ask someone to choose .
¿Cuál es tu color favorito? What is your favorite color?
¿Cuáles? Is used when there is more than one possibility to choose from.
¿Cuáles son los coches que más te gustan? Which are the cars that you like the most?
¿Qué? It is also used as a choice if que is followed by a noun.
¿Qué pastel prefieres para la fiesta? What cake do you prefer for the party?