instruction:
This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
question:
Passage: Due to its location, the Punjab region came under constant attacks and influence from the west and witnessed centuries of foreign invasions by the Greeks, Kushans, Scythians, Turks, and Afghans. The city of Taxila, founded by son of Taksh the son Bharat who was the brother of Ram. It was reputed to house the oldest university in the world,[citation needed] Takshashila University. One of the teachers was the great Vedic thinker and politician Chanakya. Taxila was a great centre of learning and intellectual discussion during the Maurya Empire. It is a UN World Heritage site, valued for its archaeological and religious history.
answer:
Who has Punjab invaded?


question:
Passage: If matter and energy are seen as necessary to explain the physical world, but incapable of explaining mind, dualism results. Emergence, holism, and process philosophy seek to ameliorate the perceived shortcomings of traditional (especially mechanistic) materialism without abandoning materialism entirely.
answer:
What is unnecessary to explain the physical world? 


question:
Passage: From the mid-2000s, the university began a number of multimillion-dollar expansion projects. In 2008, the University of Chicago announced plans to establish the Milton Friedman Institute which attracted both support and controversy from faculty members and students. The institute will cost around $200 million and occupy the buildings of the Chicago Theological Seminary. During the same year, investor David G. Booth donated $300 million to the university's Booth School of Business, which is the largest gift in the university's history and the largest gift ever to any business school. In 2009, planning or construction on several new buildings, half of which cost $100 million or more, was underway. Since 2011, major construction projects have included the Jules and Gwen Knapp Center for Biomedical Discovery, a ten-story medical research center, and further additions to the medical campus of the University of Chicago Medical Center. In 2014 the University launched the public phase of a $4.5 billion fundraising campaign. In September 2015, the University received $100 million from The Pearson Family Foundation to establish The Pearson Institute for the Study and Resolution of Global Conflicts and The Pearson Global Forum at the Harris School of Public Policy Studies.
answer:

In which decade did the university begin several thousand dollar expansion projects?