I wanted to translate this sentence on Duolingo:
"Which idea are they choosing?"
"quelle idée est-ce qu'ils choisissent"
I believe I could use the following sentences instead:
"Quelle(s) idée(s) choisissent-ils/elles."
Ils/Elles choisissent "quelle(s) idée(s)."
But I don't understand why the sentence I used is not correct. I would appreciate if you could tell me.