Most Helpful Guy
Well, that's not very difficult to figure out, why do guys ask girls if they're single? Is he working in statistics and you were part of a survey? Possible but not likely, the most likely answer is that he wanted to know before he ask you out, he respects people's relationships maybe, and wanted to make sure you were single before saying anything else,
In this case scenario your reply "why?" Is almost aggressive, cause it can imply 2 things. A) why are you asking this? We're not friends, you have no right to ask something like that. B) why do you ask? Do you like? Explain yourself!!
So if he is remotely a friend of yours a simple yes or no would have suffice0THIS IS NOT RELEVANT ANYMORE
Most Helpful Girl
If you had a fling with him, then he's seeing if you're currently involved because he probably wants to get involved with you again, whether for casual purposes or otherwise.0THIS IS NOT RELEVANT ANYMORE