Correct usage of 「您是指？」

Question

When someone responds to something I've said with「您是指？」is it accurate to assume they're saying:

"What do you mean?" - As in they want me to explain/give more info on something I've just mentioned, so it would be interchangeable with 你的意思是什么

Or

"What's that?/come again?/huh?" - More in the sense that the listener is confused or surprised by what I've just said, maybe they want me to make myself a bit clearer because they a bit taken aback by something that I just said.

Or if neither of these are correct assumptions, how would you translate 您是指？in English and what instances could it be used in?

Answer 1

It is used when someone uses some pronouns like 这件事 or 那间房子 or else to refer to something, which is not definite enough for the hearer to figure out which entity exactly the speaker is referring to. For example:

我很欣赏您的那幅作品。 I really appreciate that piece of yours.

您是指（哪一幅）？ Which one exactly are you referring to?

画了三匹马的那幅。 The one of three horses.

指 usually can mean 'refer to'.

Answer 2

I think it could mean either 'what are you referring to' or 'what do you mean' according to the context.

If one doesn't understand the whole thing and need more explanations, it's like saying what do you mean?

If one doesn't understand the specific thing someone else talks about, it will be like saying what are you referring to.