About which matter? or Which matter about? or Which matter is about? [closed]

Solution 1:

A possible dialogue could go like this:

"I'd like to talk to you about a matter."
"About which matter?"

In such a context, and choosing between the three examples you gave, that is the most reasonable answer.

But typically, especially, I think, in North America, the word that would be used more often than which.

Therefore, the following exchange could also take place:

"I'd like to talk to you about a matter."
"And that matter is about  . . . ?"

This comes close to your third example. Based on this response (which could be given), I can see the answer being phrased exactly like your third example, but it would be highly uncommon. (At least as far as I've ever heard.)

I don't believe anybody would ever use the second example, or that it's even grammatical.

As for the second question, both are fine. The first is more formal (or used by anyone who is trying to avoid ending a sentence with a preposition on the mistaken belief that doing so is ungrammatical), while the latter is more common (although not as common as other constructions).