In this task, you're given an ambiguous question (which can be answered in more than one way). Your task is to write a question that clarifies the given question in such a way that the generated question has one unique answer.

[Q]: Who is the father of emma on friends?
[A]: Which character is the father of emma on friends?


[Q]: Who sang i ain't no fortunate one?
[A]: What band sang i ain't no fortunate one in their song Fortunate Son?


[Q]: When did amazon start charging state sales tax?
[A]:
When did first amazon start charging state sales tax?