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.

Passage: The Quran describes itself as "the discernment" (al-furqān), "the mother book" (umm al-kitāb), "the guide" (huda), "the wisdom" (hikmah), "the remembrance" (dhikr) and "the revelation" (tanzīl; something sent down, signifying the descent of an object from a higher place to lower place). Another term is al-kitāb (The Book), though it is also used in the Arabic language for other scriptures, such as the Torah and the Gospels. The adjective of "Quran" has multiple transliterations including "quranic", "koranic", and "qur'anic", or capitalised as "Qur'anic", "Koranic", and "Quranic". The term mus'haf ('written work') is often used to refer to particular Quranic manuscripts but is also used in the Quran to identify earlier revealed books. Other transliterations of "Quran" include "al-Coran", "Coran", "Kuran", and "al-Qurʼan".
Which term meaning "the mother book" doesn't the Quran apply to itself?

Passage: Paleoclimatologists measure the ratio of oxygen-18 and oxygen-16 in the shells and skeletons of marine organisms to determine what the climate was like millions of years ago (see oxygen isotope ratio cycle). Seawater molecules that contain the lighter isotope, oxygen-16, evaporate at a slightly faster rate than water molecules containing the 12% heavier oxygen-18; this disparity increases at lower temperatures. During periods of lower global temperatures, snow and rain from that evaporated water tends to be higher in oxygen-16, and the seawater left behind tends to be higher in oxygen-18. Marine organisms then incorporate more oxygen-18 into their skeletons and shells than they would in a warmer climate. Paleoclimatologists also directly measure this ratio in the water molecules of ice core samples that are up to several hundreds of thousands of years old.
Who measures oxygen-18 and oxygen-16 in skeletons of all organisms?

Passage: Dell has been attempting to offset its declining PC business, which still accounted for half of its revenue and generates steady cash flow, by expanding into the enterprise market with servers, networking, software, and services. It avoided many of the acquisition writedowns and management turnover that plagued its chief rival Hewlett Packard. Dell also managed some success in taking advantage of its high-touch direct sales heritage to establish close relationships and design solutions for clients. Despite spending $13 billion on acquisitions to diversify its portfolio beyond hardware, the company was unable to convince the market that it could thrive or made the transformation in the post-PC world, as it suffered continued declines in revenue and share price. Dell's market share in the corporate segment was previously a "moat" against rivals but this has no longer been the case as sales and profits have fallen precipitously.

How much of Dell's revenue wasn't its PC division?