I haven't seen my parents for a long time.

A: _________________________________ B: I haven’t seen my parents for three months.
Which of the following choices is correct?
1)How long has it been since you saw your parents last?
2)How long haven’t you seen your parents?

2).

Hi,

I would say both 1) and 2) need some adjustment but I would rule out 2). Are you not simply asking: When did you last see your parents? or How long is it since you last saw your parents?

Alan