In this task, you're given an ambiguous question (which can be answered in more than one way). Your task is to provide one question which clarifies the input question and it has one unique answer, and also provide an answer to the generated question. Generated question and answer should be separated with a new line.

[Q]: What led to the end of indus valley civilization?
[A]: According to Sir Mortimer Wheeler in 1953, what led to the end of indus valley civilization? 
 "Aryan invasion"


[Q]: Who developed a method to mass-produce steel in america?
[A]: Who patented a method to mass-produce steel in America? 
 Henry Bessemer


[Q]: What album is the chain by fleetwood mac on?
[A]:
What album was the chain by Fleetwood Mac originally on? 
 Rumours