TASK DEFINITION: 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.
PROBLEM: Passage: Throughout the 1980s and 1990s, demand for a Scottish Parliament grew, in part because the government of the United Kingdom was controlled by the Conservative Party, while Scotland itself elected relatively few Conservative MPs. In the aftermath of the 1979 referendum defeat, the Campaign for a Scottish Assembly was initiated as a pressure group, leading to the 1989 Scottish Constitutional Convention with various organisations such as Scottish churches, political parties and representatives of industry taking part. Publishing its blueprint for devolution in 1995, the Convention provided much of the basis for the structure of the Parliament.

SOLUTION: Demand for a Scottish Parliament declined in what year?

PROBLEM: 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]

SOLUTION: what  hospitals were formed from Imperial College Healthcare?

PROBLEM: Passage: There has, however, been interest among railroad operators in returning to DC use at higher voltages than previously used. At the same voltage, DC often has less loss than AC, and for this reason high-voltage direct current is already used on some bulk power transmission lines. DC avoids the electromagnetic radiation inherent with AC, and on a railway this also reduces interference with signalling and communications and mitigates hypothetical EMF risks. DC also avoids the power factor problems of AC. Of particular interest to railroading is that DC can supply constant power with a single ungrounded wire. Constant power with AC requires three-phase transmission with at least two ungrounded wires. Another important consideration is that mains-frequency 3-phase AC must be carefully planned to avoid unbalanced phase loads. Parts of the system are supplied from different phases on the assumption that the total loads of the 3 phases will even out. At the phase break points between regions supplied from different phases, long insulated supply breaks are required to avoid them being shorted by rolling stock using more than one pantograph at a time. A few railroads have tried 3-phase but its substantial complexity has made single-phase standard practice despite the interruption in power flow that occurs twice every cycle. An experimental 6 kV DC railway was built in the Soviet Union.

SOLUTION:
Railroad operators have shown little interest in returning to what?