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: Imperial College Healthcare NHS Trust was formed on 1 October 2007 by the merger of Hammersmith Hospitals NHS Trust (Charing Cross Hospital, Hammersmith Hospital and Queen Charlotte's and Chelsea Hospital) and St Mary's NHS Trust (St. Mary's Hospital and Western Eye Hospital) with Imperial College London Faculty of Medicine. It is an academic health science centre and manages five hospitals: Charing Cross Hospital, Queen Charlotte's and Chelsea Hospital, Hammersmith Hospital, St Mary's Hospital, and Western Eye Hospital. The Trust is currently the largest in the UK and has an annual turnover of £800 million, treating more than a million patients a year.[citation needed]
what  hospitals were formed from Imperial College Healthcare?

Passage: 1,500 V DC is used in the Netherlands, Japan, Republic Of Indonesia, Hong Kong (parts), Republic of Ireland, Australia (parts), India (around the Mumbai area alone, has been converted to 25 kV AC like the rest of India), France (also using 25 kV 50 Hz AC), New Zealand (Wellington) and the United States (Chicago area on the Metra Electric district and the South Shore Line interurban line). In Slovakia, there are two narrow-gauge lines in the High Tatras (one a cog railway). In Portugal, it is used in the Cascais Line and in Denmark on the suburban S-train system.
In Romania, there are two narrow-gauge lines where?

Passage: Meanwhile, he had written to Abu Ya'far, the prefect of the dynamic city of Isfahan, offering his services. The new emir of Hamadan, hearing of this correspondence and discovering where Ibn Sina was hiding, incarcerated him in a fortress. War meanwhile continued between the rulers of Isfahan and Hamadãn; in 1024 the former captured Hamadan and its towns, expelling the Tajik mercenaries. When the storm had passed, Ibn Sina returned with the emir to Hamadan, and carried on his literary labors. Later, however, accompanied by his brother, a favorite pupil, and two slaves, Ibn Sina escaped from the city in the dress of a Sufi ascetic. After a perilous journey, they reached Isfahan, receiving an honorable welcome from the prince.

What prefect wrote to Ibn Sani offering him a position?