Q: 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: Utrecht is the centre of a densely populated area, which makes concise definitions of its agglomeration difficult, and somewhat arbitrary. The smaller Utrecht agglomeration of continuously built up areas counts some 420,000 inhabitants and includes Nieuwegein, IJsselstein and Maarssen. It is sometimes argued that the close by municipalities De Bilt, Zeist, Houten, Vianen, Driebergen-Rijsenburg (Utrechtse Heuvelrug), and Bunnik should also be counted towards the Utrecht agglomeration, bringing the total to 640,000 inhabitants. The larger region, including slightly more remote towns such as Woerden and Amersfoort counts up to 820,000 inhabitants.
A:
What is the population of the original bishopric?