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: Oxygen was discovered independently by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, and Joseph Priestley in Wiltshire, in 1774, but Priestley is often given priority because his work was published first. The name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. Its name derives from the Greek roots ὀξύς oxys, "acid", literally "sharp", referring to the sour taste of acids and -γενής -genes, "producer", literally "begetter", because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition. Common uses of oxygen includes the production cycle of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, in oxygen therapy and life support systems in aircraft, submarines, spaceflight and diving.
answer:
When did Carl Priestly discover oxygen?


question:
Passage: Dell announced a change campaign called "Dell 2.0," reducing the number of employees and diversifying the company's products. While chairman of the board after relinquishing his CEO position, Michael Dell still had significant input in the company during Rollins' years as CEO. With the return of Michael Dell as CEO, the company saw immediate changes in operations, the exodus of many senior vice-presidents and new personnel brought in from outside the company. Michael Dell announced a number of initiatives and plans (part of the "Dell 2.0" initiative) to improve the company's financial performance. These include elimination of 2006 bonuses for employees with some discretionary awards, reduction in the number of managers reporting directly to Michael Dell from 20 to 12, and reduction of "bureaucracy". Jim Schneider retired as CFO and was replaced by Donald Carty, as the company came under an SEC probe for its accounting practices.
answer:
What wasn't the name of Dell's change campaign?


question:
Passage: The ASA standard underwent a major revision in 1960 with ASA PH2.5-1960, when the method to determine film speed was refined and previously applied safety factors against under-exposure were abandoned, effectively doubling the nominal speed of many black-and-white negative films. For example, an Ilford HP3 that had been rated at 200 ASA before 1960 was labeled 400 ASA afterwards without any change to the emulsion. Similar changes were applied to the DIN system with DIN 4512:1961-10 and the BS system with BS 1380:1963 in the following years.
answer:

When were new safety factors put in place?