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: Where every component state of a federation possesses the same powers, we are said to find 'symmetric federalism'. Asymmetric federalism exists where states are granted different powers, or some possess greater autonomy than others do. This is often done in recognition of the existence of a distinct culture in a particular region or regions. In Spain, the Basques and Catalans, as well as the Galicians, spearheaded a historic movement to have their national specificity recognized, crystallizing in the "historical communities" such as Navarre, Galicia, Catalonia, and the Basque Country. They have more powers than the later expanded arrangement for other Spanish regions, or the Spain of the autonomous communities (called also the "coffee for everyone" arrangement), partly to deal with their separate identity and to appease peripheral nationalist leanings, partly out of respect to specific rights they had held earlier in history. However, strictly speaking Spain is not a federalism, but a decentralized administrative organization of the state.
What does no components state of federation possess?

Passage: Normans came into Scotland, building castles and founding noble families who would provide some future kings, such as Robert the Bruce, as well as founding a considerable number of the Scottish clans. King David I of Scotland, whose elder brother Alexander I had married Sybilla of Normandy, was instrumental in introducing Normans and Norman culture to Scotland, part of the process some scholars call the "Davidian Revolution". Having spent time at the court of Henry I of England (married to David's sister Maud of Scotland), and needing them to wrestle the kingdom from his half-brother Mael Coluim mac Alaxandair, David had to reward many with lands. The process was continued under David's successors, most intensely of all under William the Lion. The Norman-derived feudal system was applied in varying degrees to most of Scotland. Scottish families of the names Bruce, Gray, Ramsay, Fraser, Ogilvie, Montgomery, Sinclair, Pollock, Burnard, Douglas and Gordon to name but a few, and including the later royal House of Stewart, can all be traced back to Norman ancestry.
Who did King David I of Scotland Marry?

Passage: On tracks that London Underground share with National Rail third-rail stock (the Bakerloo and District lines both have such sections), the centre rail is connected to the running rails, allowing both types of train to operate, at a compromise voltage of 660 V. Underground trains pass from one section to the other at speed; lineside electrical connections and resistances separate the two types of supply. These routes were originally solely electrified on the four-rail system by the LNWR before National Rail trains were rewired to their standard three-rail system to simplify rolling stock use.
What joins the two types of supply?