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.

Input: Consider Input: Passage: Shell's primary business is the management of a vertically integrated oil company. The development of technical and commercial expertise in all stages of this vertical integration, from the initial search for oil (exploration) through its harvesting (production), transportation, refining and finally trading and marketing established the core competencies on which the company was founded. Similar competencies were required for natural gas, which has become one of the most important businesses in which Shell is involved, and which contributes a significant proportion of the company's profits. While the vertically integrated business model provided significant economies of scale and barriers to entry, each business now seeks to be a self-supporting unit without subsidies from other parts of the company.

Output: What is the least important business for Shell?

Input: Consider Input: Passage: The original post-punk movement ended as the bands associated with the movement turned away from its aesthetics, often in favor of more commercial sounds. Many of these groups would continue recording as part of the new pop movement, with entryism becoming a popular concept. In the United States, driven by MTV and modern rock radio stations, a number of post-punk acts had an influence on or became part of the Second British Invasion of "New Music" there. Some shifted to a more commercial new wave sound (such as Gang of Four), while others were fixtures on American college radio and became early examples of alternative rock. Perhaps the most successful band to emerge from post-punk was U2, who combined elements of religious imagery together with political commentary into their often anthemic music.

Output: What did bands associated with post-punk never turn away from?

Input: Consider Input: Passage: The fortified city temporarily fell to the French invasion in 1672 (the Disaster Year); where the French invasion was only stopped west of Utrecht at the Old Hollandic Waterline. In 1674, only two years after the French left, the centre of Utrecht was struck by a tornado. The halt to building before construction of flying buttresses in the 15th century now proved to be the undoing of the central section of the cathedral of St Martin church which collapsed; creating the current Dom square between the tower and choir. In 1713, Utrecht hosted one of the first international peace negotiations when the Treaty of Utrecht settled the War of the Spanish Succession. Since 1723 Utrecht became the centre of the non-Roman Old Catholic Churches in the world.
Output: Who did the city fall to in the 16th century?