"Which is it?"
I tried with "qual'è" and it was correct. And Duolingo tells me is "qual è" (without the apostrophe) is also right. And I just read somewhere that if you use the stressed "è" you shouldn't use the apostrophe, and that that's a very common mistake that a lot of people still make. Can some native Italian tell me if that's true, or if they mean exactly the same, or if one's more informal than the other? (Please excuse my poor English...)
"quali" and "quale" I think are for masculine and feminine nouns. "quale" is used for both masculine and feminine singular, while ( I think) "quali" is used for masculine and feminine plural. In this translation you wouldn't use 'quali" or "quale" because the word that follows is a verb and not a noun. So the translation shortens to "qual e"