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.
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Question: Who created the plan that became known as the american system?

Answer: Who  was the creation of the American System based on?


Question: Who has the fastest selling album of all time?

Answer: What is the fastest selling album of all time in Canada?


Question: At what age do you start high school?

Answer:
At what age do the youngest students typically enter 9th grade in US high schools?