instruction:
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.
question:
Who has scored the most goals for chelsea?
answer:
Who has scored the most goals for Chelsea F.C. in total?


question:
Who was formula one world champion four times in a row from 2010 to 2013?
answer:
What driver was formula one world champion four times in a row from 2010 to 2013?


question:
When did us airways and american airlines merger?
answer:

When did us airways and american airlines begin their merger?