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.
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Question: Passage: Glass has the ability to refract, reflect, and transmit light following geometrical optics, without scattering it. It is used in the manufacture of lenses and windows. Common glass has a refraction index around 1.5. This may be modified by adding low-density materials such as boron, which lowers the index of refraction (see crown glass), or increased (to as much as 1.8) with high-density materials such as (classically) lead oxide (see flint glass and lead glass), or in modern uses, less toxic oxides of zirconium, titanium, or barium. These high-index glasses (inaccurately known as "crystal" when used in glass vessels) cause more chromatic dispersion of light, and are prized for their diamond-like optical properties.

Answer: What can be used to make glass less dense?


Question: Passage: Harvard's academic programs operate on a semester calendar beginning in early September and ending in mid-May. Undergraduates typically take four half-courses per term and must maintain a four-course rate average to be considered full-time. In many concentrations, students can elect to pursue a basic program or an honors-eligible program requiring a senior thesis and/or advanced course work. Students graduating in the top 4–5% of the class are awarded degrees summa cum laude, students in the next 15% of the class are awarded magna cum laude, and the next 30% of the class are awarded cum laude. Harvard has chapters of academic honor societies such as Phi Beta Kappa and various committees and departments also award several hundred named prizes annually. Harvard, along with other universities, has been accused of grade inflation, although there is evidence that the quality of the student body and its motivation have also increased. Harvard College reduced the number of students who receive Latin honors from 90% in 2004 to 60% in 2005. Moreover, the honors of "John Harvard Scholar" and "Harvard College Scholar" will now be given only to the top 5 percent and the next 5 percent of each class.

Answer: What does a basic program also require?


Question: Passage: In 1987, in Canada, Elizabeth publicly supported politically divisive constitutional amendments, prompting criticism from opponents of the proposed changes, including Pierre Trudeau. The same year, the elected Fijian government was deposed in a military coup. Elizabeth, as monarch of Fiji, supported the attempts of the Governor-General, Ratu Sir Penaia Ganilau, to assert executive power and negotiate a settlement. Coup leader Sitiveni Rabuka deposed Ganilau and declared Fiji a republic. By the start of 1991, republican feeling in Britain had risen because of press estimates of the Queen's private wealth—which were contradicted by the Palace—and reports of affairs and strained marriages among her extended family. The involvement of the younger royals in the charity game show It's a Royal Knockout was ridiculed and the Queen was the target of satire.

Answer:
What government was Pierre Trudeau prime minister of in 1987?